Okto Nexus

Local-first coordination for teams of AI agents.

Okto Nexus is an MCP server and operator hub for agents working in the same repository. It gives them durable identities, presence, messages, inboxes, handoffs, artifacts, an event log, governance controls, and a live dashboard without requiring a cloud broker.

okto-nexus serve exposes the complete hub on one port:

• /mcp — MCP over streamable HTTP, authenticated as an agent;
• /api/v1 — operator REST APIs, read-only monitor endpoints, and SSE;
• / — the bundled React dashboard.

The classic stdio transport remains supported. Coordination records live in one SQLite database in WAL mode. Optional metrics, referenced workspace files, and the derived shared.md view live outside that database.

Release fact	Value
Package	okto-nexus 0.1.3
Python	>=3.11
MCP surface	43 tools by default; 46 with memory enabled
MCP resources	12 versioned reference resources
MCP prompts	0
Surface revision	31
Database schema	26 migrations, 34 tables
Storage	local SQLite/WAL

• PyPI: pypi.org/project/okto-nexus
• Source: github.com/OktoLabsAI/okto-nexus

Contents

• Why Nexus
• Install
• Start the hub
• Connect an MCP client
• Agent pre-flight
• Architecture
• HTTP surfaces and authentication
• Dashboard
• Coordination model
• MCP surface
• Configuration
• Operations
• Data model and migrations
• Errors
• Development
• Troubleshooting
• Security and limitations
• Release notes
• License

Why Nexus

• One coordination space per project. An absolute project_root is canonicalized and hashed into a deterministic workspace_id. Every client that resolves the same real path joins the same workspace.
• Durable delivery. Messages fan out into per-recipient inbox lanes with leases, redelivery, acknowledgements, delivery status, and optional read receipts.
• Single-winner work dispatch. Handoffs support atomic claim, leases, rejection, cancellation, optional verification, and optional dependency graphs.
• Explicit identity and presence. Operators create identities and API keys; agents open sessions and heartbeat to remain present.
• Targeted routing. Direct, capability, role, tag, broadcast, mixed, and direct-with-fallback strategies share one validated grammar.
• Governed communication. Permissions, communication scopes, versioned policies, quotas, guardrails, groups, and human approval can restrict writes without exposing the control plane to agents.
• Observable by design. Monotonic event IDs, cursor reads, long-poll, replay export, SSE, health aggregates, and a live dashboard expose what the team is doing.
• Local-first and fail-closed. Configuration, target grammars, catalogs, workspace paths, API keys, and state transitions are validated before writes.
• Token-aware MCP docs. First-use guidance remains resident; deeper reference material is available through versioned MCP resources on demand.

Install

The recommended install includes the HTTP hub, dashboard, local embedding provider, and tokenizer:

uv tool install "okto-nexus[serve]"
okto-nexus serve

Equivalent with pipx:

pipx install "okto-nexus[serve]"

Available extras:

Extra	Includes	Use it when
none	stdio MCP core	You only need a lightweight local stdio server
serve-lite	FastAPI, Uvicorn, dashboard	You need HTTP without Torch/model dependencies
embeddings	sentence-transformers	You want the local embedding provider separately
serve	HTTP stack, embeddings, tokenizer	You want the complete supported hub
dev	pytest, FastAPI, Uvicorn, httpx	You are developing or testing Nexus

The published wheel and sdist contain the compiled dashboard. Node.js is only needed when rebuilding the frontend from source.

From a checkout:

git clone https://github.com/OktoLabsAI/okto-nexus.git
cd okto-nexus
uv sync --extra dev

# Complete HTTP build:
uv sync --extra serve --extra dev

Start the hub

okto-nexus serve

Defaults:

• dashboard: http://127.0.0.1:8202/;
• MCP: http://127.0.0.1:8202/mcp;
• data directory: ~/.okto_nexus;
• database: ~/.okto_nexus/nexus.db;
• initial workspace context: the current directory. The dashboard keeps a saved selection when present and otherwise may open the all-workspaces view.

Useful variants:

okto-nexus serve --project-root /absolute/path/to/project
okto-nexus serve --host 0.0.0.0 --port 8202
okto-nexus serve --trust-mode strict
okto-nexus serve --embedding-mode local

On first use, open Agents → New agent in the dashboard. Create one identity per participant and copy its nxs_... key immediately: Nexus stores only the hash and shows plaintext only at creation or regeneration. Capability and tag values must first exist in Registry before an identity can use them.

Connect an MCP client

The dashboard generates snippets for Claude Code, Claude Desktop, Codex, Cursor, VS Code, Windsurf, and Cline. The generic streamable-HTTP URL is:

http://127.0.0.1:8202/mcp?api_key=nxs_REPLACE_ME

Credential extraction order is query api_key, x-api-key header, then Authorization: Bearer. Treat client configuration containing a query key as a secret.

Examples:

claude mcp add -t http okto-nexus \
  "http://127.0.0.1:8202/mcp?api_key=nxs_REPLACE_ME"

codex mcp add okto-nexus \
  --url "http://127.0.0.1:8202/mcp?api_key=nxs_REPLACE_ME"

Generic JSON:

{
  "mcpServers": {
    "okto-nexus": {
      "url": "http://127.0.0.1:8202/mcp?api_key=nxs_REPLACE_ME"
    }
  }
}

Stdio

Run okto-nexus without a subcommand for stdio:

{
  "mcpServers": {
    "okto-nexus": {
      "command": "okto-nexus",
      "args": [],
      "env": {
        "OKTO_NEXUS_HOME": "/absolute/path/to/nexus-home"
      }
    }
  }
}

Without OKTO_NEXUS_API_KEY, stdio preserves the cooperative anonymous model. Set that variable to an active nxs_... key to bind the process to the same authenticated identity rules as HTTP. An invalid configured key fails closed.

Agent pre-flight

Every authenticated agent should do this on its first turn:

1. Call agent_whoami() and use the returned agent_id consistently.
2. Call workspace_resolve(project_root=<absolute cwd>).
3. Call session_open(agent_id=<you>, workspace_id=<resolved id>) and retain the returned session_id and one-time session_secret.
4. Check inbox_count(agent_id=<you>); pull and acknowledge backlog.
5. Anchor monitoring with event_cursor(project_root=..., agent_id=<you>, stream="workspace").

The full procedure is available at okto-nexus://reference/preflight.

Direct message

{
  "project_root": "/absolute/path/to/project",
  "from_agent_id": "researcher",
  "subject": "API findings",
  "body": "The endpoint is idempotent; details are attached.",
  "target": {
    "strategy": "direct",
    "agent_id": "implementer"
  },
  "from_session_id": "ses_...",
  "session_secret": "..."
}

The response names the resolved recipients and delivery count. The recipient uses:

inbox_count(agent_id="implementer")
inbox_pull(agent_id="implementer", session_id="ses_...", session_secret="...")
inbox_ack(agent_id="implementer", message_ids=[...],
          session_id="ses_...", session_secret="...")

Messages are delivered through the inbox. event_get and event_wait are observability tools, not delivery.

Long-poll

event_wait is a snapshot when timeout_seconds is omitted, null, or 0. Long-poll is explicit:

event_wait(
  project_root="/absolute/path/to/project",
  agent_id="researcher",
  stream="workspace",
  cursor=123,
  timeout_seconds=25,
  profile="summary"
)

Always continue from next_cursor. The waiter uses SQLite PRAGMA data_version plus bounded sleep polling; HTTP runs the blocking wait in a worker thread so it does not block the shared event loop.

Architecture

MCP stdio             MCP HTTP              REST / SSE / SPA        CLI
    \                     |                         |                 /
     +---------------- inbound adapters and transport auth ----------------+
                                      |
                             application services
       identity · messages · inbox · handoffs · events · artifacts
       permissions · policies · approvals · guardrails · memory · health
                                      |
                         domain models and pure rules
                                      |
      +------------------------- outbound ports ---------------------------+
      | SQLite repositories | files/shared.md | waiter | telemetry | embed |
      +--------------------------------------------------------------------+

bootstrap() resolves configuration, creates the store, applies migrations, wires repositories, telemetry, embeddings, and approval execution, then seeds the reserved operator, backfills the capability catalog, and creates built-in permission/communication presets. create_server() lazily imports FastMCP and registers the effective tools and resources. serve wraps the same composition in FastAPI/Uvicorn; tail and admin are separate CLI adapters.

Important boundaries:

• domain code contains state machines, routing, IDs, and invariants;
• application services own the core coordination use cases; operator CRUD/maintenance routes may drive repositories and units of work directly;
• inbound adapters translate MCP, HTTP, SSE, and CLI calls;
• outbound adapters implement SQLite, files, telemetry, tokenization, embeddings, and waiting;
• coordination truth is durable in SQLite; bounded process caches are implementation details, not authoritative state.

HTTP surfaces and authentication

Surface	Loopback bind	Non-loopback bind
SPA shell/assets, /healthz, info, license	Public	Public
REST data/control plane	Keyless operator trust	Active nxs_ key required
MCP /mcp	Active nxs_ key required	Active nxs_ key required
EPT monitor endpoints	Scoped nxsept_ accepted	Scoped nxsept_ accepted

MCP-over-HTTP connections always represent an agent; stdio may use the cooperative anonymous mode. The dashboard/REST loopback trust path represents the local operator. Browser-origin checks protect mutating operator routes, and binding beyond loopback removes keyless REST trust.

On a non-loopback bind, use the reserved operator identity's key for the dashboard/control plane. Participant keys authenticate requests but operator-only routes return PERMISSION_DENIED. When a store has no keys at all, startup creates the operator key and prints its plaintext once.

Permanent agent keys can authenticate REST and MCP, but helper monitors should receive only a short-lived ephemeral poll token (nxsept_...). EPTs are bound to the issuing session, agent, and workspace and are accepted only as Authorization: Bearer nxsept_...; query api_key and x-api-key are rejected for this token type. The bearer is valid only on:

• GET /api/v1/events and GET /api/v1/events/cursor;
• GET /api/v1/inbox/count and GET /api/v1/inbox/peek.

They cannot call MCP or mutate state.

Dashboard

The bundled dashboard provides:

• Graph — agent cards, heartbeat-derived presence, recent message flow, unread traffic, open handoffs, and claimed relationships;
• Messages — inbox lanes, peer conversations, undelivered targeting outcomes, receipts, and optional semantic search;
• Handoffs — a six-column Kanban including VERIFYING, claim details, dependency state, verification, cancellation, and results;
• Events — filtered event history, trace navigation, and live SSE updates;
• Memory — durable memory browse/search/curation when feature_memory is enabled;
• Workspaces — sessions, analytics, and coordination health;
• Agents — identities, keys, activation, roles, capabilities, metadata, colors, permissions, tags, inbound/outbound audiences, communication style, and steering;
• Registry — operator-managed capability and tag vocabularies;
• Policies — versioned policies and per-agent bindings;
• Guardrails — groups, versioned content rules, assignments, and scrubbed denial audit;
• Communication — versioned communication presets and bindings;
• Approvals — pending and decided human-in-the-loop actions;
• Settings — runtime-manageable settings, feature flags, retention, and database maintenance; metrics use their own header-menu panel.

Semantic search requires embedding_mode=stub or local. off returns EMBEDDINGS_UNAVAILABLE on the REST search endpoint. The local provider needs the embeddings extra; stub is deterministic and is intended for tests or demonstrations.

Coordination model

Workspaces, agents, and sessions

• Agents are global identities; workspaces represent canonical project roots.
• Most coordination tools accept project_root.
• session_open and shared_md_render consume a resolved workspace_id.
• An authenticated agent can update only its own profile with agent_register, subject to identity.update_profile and identity.update_capabilities. Operators create identities.
• Authenticated discovery is reachability-scoped. agent_list and agent_get hide unreachable peers; capability_list returns the complete catalog but filters owner identities.
• workspace_list is permission-gated; absolute paths require a separate permission.
• Cross-workspace errors are intentionally operation-specific: WORKSPACE_MISMATCH for ownership guards, NOT_FOUND for hidden artifact or memory reads, and DEPENDENCY_NOT_FOUND for dependency creation.

Presence is explicit. A session is considered present while its heartbeat is within presence_ttl_seconds. A trust-sensitive write advances the heartbeat only when it authenticates with that session's credentials; in trust_mode=open, a credential-free write advances no session. Read-only tools do not heartbeat. Call session_heartbeat during long read-only or idle periods and session_close when finished.

Messages and inboxes

message_create persists one message and resolves recipients at send time. Each recipient gets a durable delivery row in its global inbox. The lanes are:

Lane	Meaning
unread	Available to pull
delivered	Pulled and protected by an in-flight lease
read	Acknowledged
parked	Dead-lettered after exhausting delivery claims; not redelivered automatically

An expired delivered lease becomes pullable again. Delivery is therefore at-least-once until acknowledgement. message_status lets the sender inspect each recipient's lane. Every pull/redelivery emits message.delivered; ack emits message.read. By default, ack also sends one synthetic read-receipt message to the sender; receipts do not recursively create receipts.

Channels are organizational labels, not ACLs or delivery mechanisms. Access still intersects with permissions, policy, guardrails, and communication reachability. Message retention can remove aged messages and their deliveries, including unread or in-flight rows, so durability is bounded by configured retention and explicit database reset.

Routing

There are seven strategies:

Strategy	Descriptor	Notes
direct	{"strategy":"direct","agent_id":"a"}	One named identity
capability	{"strategy":"capability","capability":"review"}	One or any of several registered capabilities
role	{"strategy":"role","role":"reviewer"}	Exact role match
tag	{"strategy":"tag","selector":{"team":["platform"]}}	Registered tag selector
broadcast	{"strategy":"broadcast"}	Present workspace agents for messages; globally registered eligible agents for handoffs
mixed	{"strategy":"mixed","rules":[...]}	Non-empty union of non-broadcast rules
direct_with_fallback	direct plus fallback_after_seconds and optional fallback	Handoffs only

Messages support direct, capability, role, tag, broadcast, and mixed. Omitting a message target means broadcast. Handoffs require an explicit target and additionally support direct-with-fallback.

Tag selectors use AND across keys and OR across values. Rich In/NotIn/Exists/DoesNotExist expressions are also supported. Capability and tag names fail closed against operator-managed catalogs.

Target resolution is intersected with presence where applicable and with the caller's effective communication reach/audience. Separate enforcement layers then allow, deny, limit, or intercept the write:

• per-agent permissions and recipient/rate limits;
• versioned policy action rules and quotas;
• content guardrails;
• optional HITL approval interception.

A channel itself adds no ACL. Visibility controls who may see an item; eligibility controls who may claim it.

Event log

Events are immutable after insertion during normal operation. event_id is globally monotonic and never reused. Retention may delete old rows, so retained history can contain gaps.

Streams are workspace, agent, and handoff. Supported filters are type, agent_id, task_id, handoff_id, and trace_id. Authenticated event reads require events.read and omit actors outside the caller's communication reach, except the caller's own and system events.

Response profiles:

Profile	Behavior
default	Safe trim: preserves contextual fields while removing empty or duplicated data; oversized event payloads can yield a follow-up hint
summary	Aggressive projection: omits heavy bodies/payloads and returns follow-up hints
full	Raw debugging escape hatch

event_get is non-blocking. event_cursor returns the current end in O(1). event_wait long-polls only when timeout_seconds > 0. Dashboard SSE already provides operator UI updates; agent monitoring remains MCP polling/long-poll or the EPT read-only REST plane.

Handoffs

OPEN      -> CLAIMED
OPEN      -> REJECTED | CANCELLED
CLAIMED   -> COMPLETED
CLAIMED   -> VERIFYING        when acceptance criteria exist
CLAIMED   -> REJECTED         claimant rejects
CLAIMED   -> OPEN             lease expires
VERIFYING -> COMPLETED        verifier passes
VERIFYING -> CLAIMED          verifier fails; executor reworks

Only one agent wins handoff_claim. A claim returns the confidential payload. Available-list responses omit payload; handoff_get includes it only for the claimant. Events and synthetic notifications never carry the payload.

With feature_verification=true, creation may include acceptance_criteria and verify_by. The executor cannot verify its own result. A failed verdict persists feedback, returns the handoff to CLAIMED, and renews the lease.

With feature_dag=true, creation may include depends_on. The persisted status remains OPEN, but blockedness is derived. Blocked items are excluded from handoff_list_available and claim returns DEPENDENCY_NOT_MET until every dependency is COMPLETED.

Artifacts and shared.md

Artifacts are either inline text/json/markdown or a workspace-contained file reference. Path containment is checked after canonical resolution; escapes return PATH_OUTSIDE_WORKSPACE. Inline content is bounded by max_inline_bytes.

The publisher's effective outbound audience is frozen on the artifact. The same audience controls artifact.created visibility and artifact_get. Unauthorized, cross-workspace, and missing reads all return NOT_FOUND.

shared_md_render atomically rewrites a derived workspace shared.md with four fixed sections: relevant agents/sessions, open tasks, open handoffs, and recent events. It never becomes the source of truth and never renders handoff payloads. Authenticated callers need shared_md.render.

Permissions, policies, guardrails, and approvals

The operator control plane manages:

• permission presets and per-agent effective permissions;
• capability/tag catalogs and communication scopes;
• versioned attachable policies with deny-overrides and quota windows;
• versioned communication guidance returned privately by agent_whoami;
• agent groups and versioned guardrails assigned by scope and priority;
• one-shot HITL approval decisions and operator steering.

Guardrail denials persist scrubbed metadata, not rejected raw content. When feature_hitl=true and a policy requires approval, message_create or handoff_create may return status: "pending_approval". Do not resend the action; watch the returned approval ID.

Opt-in features

All seven flags default to off:

Flag	Effect
feature_trace	Accept and project trace_id correlation
feature_hitl	Enable new require_approval interception
feature_verification	Enable handoff acceptance criteria and verdicts
feature_dag	Enable handoff dependencies
feature_memory	Register three memory MCP tools and show Memory UI; restart required
feature_health	Enable coordination_health MCP execution
feature_replay	Enable REST replay export

Nuances:

• approval history and decisions remain available when interception is off;
• disabling verification or DAG blocks new contracts/dependencies, while already persisted workflow state remains enforceable and decidable;
• workspace health REST remains available when the MCP health flag is off;
• CLI replay export is operator-shell access and is not gated by feature_replay;
• memory REST supports operator curation independently, but MCP memory tools are registered only when the flag is on at startup.

MCP surface

The default server exposes 43 tools: 42 across tool modules plus nexus_info. Enabling feature_memory at startup adds three tools, for 46. Both transports expose the same effective tool/resource surface for the same configuration.

Area	Tools
Metadata	nexus_info
Identity/workspace	workspace_resolve, agent_register, agent_whoami, session_open, session_heartbeat, session_close, workspace_list, agent_list, agent_get, capability_list
Events	event_get, event_cursor, event_wait
Messages/channels	message_create, channel_create, channel_list, message_get, message_list, message_wait
Inbox	inbox_pull, inbox_ack, inbox_extend, inbox_peek, inbox_count, inbox_history, message_status
Handoffs	handoff_create, handoff_list_available, handoff_claim, handoff_complete, handoff_verify, handoff_reject, handoff_cancel, handoff_get
Artifacts	artifact_put, artifact_get
Derived view	shared_md_render
Health	coordination_health
Catalog	tag_list
Ephemeral monitor tokens	poll_token_issue, poll_token_renew, poll_token_revoke
Optional memory	memory_put, memory_get, memory_search

message_get, message_list, and message_wait are intentional migration shims. They return MIGRATED with replacements in the inbox/event surface instead of failing as unknown tools.

coordination_health stays registered but returns VALIDATION_ERROR while feature_health is off. memory_put/get/search are absent until feature_memory is enabled and the server restarts.

Session credentials are trust-sensitive on:

• message_create;
• handoff_claim/complete/verify/reject/cancel;
• inbox_pull/ack/extend;
• memory_put when published.

In trust_mode=open they are optional but validated if supplied. In trust_mode=strict they are required. poll_token_issue/renew/revoke always require a valid session_id and session_secret in both modes.

Versioned MCP resources

URI	Version
okto-nexus://reference/preflight	3
okto-nexus://reference/communication	2
okto-nexus://reference/monitoring	5
okto-nexus://reference/target-grammar	5
okto-nexus://reference/tool-docs/messages	2
okto-nexus://reference/tool-docs/inbox	2
okto-nexus://reference/tool-docs/events	2
okto-nexus://reference/tool-docs/handoff	3
okto-nexus://reference/tool-docs/identity	4
okto-nexus://reference/tool-docs/artifacts	2
okto-nexus://reference/governance	2
okto-nexus://reference/hitl	2

nexus_info reports package/schema/surface versions, the URI-to-version map, and effective feature flags. Use that live metadata instead of assuming a cached surface.

Response envelope

Successful tools return:

{
  "ok": true,
  "data": {}
}

Failures return:

{
  "ok": false,
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Human-readable explanation"
  }
}

Transient SQLite lock/busy failures use DB_ERROR with details.retryable=true.

Resident token footprint

For the 0.1.3 default surface:

Component	Characters
Server instructions	3,992
Tool docstrings	6,563
Parameter schemas/descriptions	15,720
Cuttable resident surface	26,275 (~6,568 tokens)
Total measured surface	37,345 (~9,336 tokens)

Deep explanations live in resources so clients load them only when needed. The current measured cuttable reduction against the frozen baseline is about 44.3%.

Configuration

For serve settings managed by the runtime catalog, effective precedence is:

CLI flag > environment variable > stored dashboard override > default

Within the core/stdio bootstrap there is no stored layer, so precedence is CLI > env > default. Unknown flags, missing values, invalid enums, and out-of-range numbers fail closed with CONFIG_ERROR. Boolean CLI flags take an explicit value such as --feature-trace true.

Core runtime

Environment	CLI	Default	Notes
OKTO_NEXUS_HOME	--home	~/.okto_nexus	Runtime data directory
OKTO_NEXUS_DB_PATH	--db-path	{home}/nexus.db	SQLite database
OKTO_NEXUS_BUSY_TIMEOUT_MS	--busy-timeout-ms	5000	Minimum 0
OKTO_NEXUS_POLL_INTERVAL_MS	--poll-interval-ms	200	Waiter interval; minimum 1
OKTO_NEXUS_MAX_WAIT_TIMEOUT_SECONDS	--max-wait-timeout-seconds	30	Server wait ceiling; minimum 0
OKTO_NEXUS_HANDOFF_LEASE_TTL_SECONDS	--handoff-lease-ttl-seconds	300	Minimum 1
OKTO_NEXUS_MAX_INLINE_BYTES	--max-inline-bytes	65536	Inline artifact/content limit
OKTO_NEXUS_INBOX_LEASE_TTL_SECONDS	--inbox-lease-ttl-seconds	300	Minimum 1
OKTO_NEXUS_SESSION_STALE_TTL_SECONDS	--session-stale-ttl-seconds	60	Derived stale threshold
OKTO_NEXUS_PRESENCE_TTL_SECONDS	--presence-ttl-seconds	1800	Broadcast/tag presence window
OKTO_NEXUS_SESSION_REAP_SECONDS	--session-reap-seconds	86400	Opportunistic stale close
OKTO_NEXUS_MAX_SHARED_MD_EVENTS	--max-shared-md-events	1000	Render ceiling
OKTO_NEXUS_MAX_EVENT_LIMIT	--max-event-limit	1000	Event page ceiling
OKTO_NEXUS_POLL_TOKEN_TTL_SECONDS	--poll-token-ttl-seconds	3600	Minimum 60
OKTO_NEXUS_TRUST_MODE	--trust-mode	open	open or strict
OKTO_NEXUS_EMBEDDING_MODE	--embedding-mode	off	off, stub, or local
OKTO_NEXUS_INBOX_READ_RECEIPTS	--inbox-read-receipts	true	Sender inbox receipts
OKTO_NEXUS_EXPOSE_WORKSPACE_PATH	--expose-workspace-path	false	Operator REST/dashboard path disclosure
OKTO_NEXUS_AUTO_PRUNE_ON_START	--auto-prune-on-start	false	One bounded best-effort startup pass

Retention

Environment	CLI	Default	Minimum
OKTO_NEXUS_RETENTION_EVENTS_KEEP_DAYS	--retention-events-keep-days	30	0
OKTO_NEXUS_RETENTION_READ_DELIVERIES_KEEP_DAYS	--retention-read-deliveries-keep-days	14	0
OKTO_NEXUS_RETENTION_CLOSED_SESSIONS_KEEP_DAYS	--retention-closed-sessions-keep-days	7	0
OKTO_NEXUS_RETENTION_MESSAGES_KEEP_DAYS	--retention-messages-keep-days	30	7

Pruning removes aged events, read deliveries, closed sessions, and messages older than the message window. Message retention is pure-age: it can remove unread, in-flight, or parked messages and cascades to their deliveries and embeddings. Handoffs and other non-message live rows are not age-pruned.

Metrics

Environment	CLI	Default	Notes
OKTO_NEXUS_METRICS_MODE	--metrics-mode	disabled	disabled, local_only, anonymous_beacon
OKTO_NEXUS_METRICS_DIR	--metrics-dir	{home}/metrics	Local telemetry JSONL/state
OKTO_NEXUS_METRICS_BEACON_URL	--metrics-beacon-url	https://nexus-metrics.oktolabs.ai	Used only in beacon mode
OKTO_NEXUS_METRICS_RETENTION_DAYS	--metrics-retention-days	30	Minimum 0
OKTO_NEXUS_METRICS_PUBLISH_INTERVAL_SECONDS	--metrics-publish-interval-seconds	3600	Minimum 60

Metrics are opt-in. Local mode stores bounded per-event metadata; beacon mode publishes aggregate hourly counts only. Message bodies, prompts, workspace file paths, coordination IDs, keys, tokens, URLs, and stack traces are excluded. Local telemetry JSONL is not currently pruned automatically; operators must manage those files even though metrics_retention_days is validated and exposed in configuration.

Feature flags

Environment	CLI	Default
OKTO_NEXUS_FEATURE_TRACE	--feature-trace	false
OKTO_NEXUS_FEATURE_HITL	--feature-hitl	false
OKTO_NEXUS_FEATURE_VERIFICATION	--feature-verification	false
OKTO_NEXUS_FEATURE_DAG	--feature-dag	false
OKTO_NEXUS_FEATURE_MEMORY	--feature-memory	false
OKTO_NEXUS_FEATURE_HEALTH	--feature-health	false
OKTO_NEXUS_FEATURE_REPLAY	--feature-replay	false

feature_memory changes tool registration and requires restart/reconnect. The other flags gate live behavior.

Serve-only and transport-specific settings

Environment	CLI	Default	Scope
OKTO_NEXUS_PORT	--port	8202	serve
OKTO_NEXUS_HOST	--host	127.0.0.1	serve
OKTO_NEXUS_LOG_LEVEL	--log-level	warning	critical through trace
—	--project-root	.	Initial dashboard workspace
OKTO_NEXUS_NO_BANNER	—	unset	Suppress serve banner
OKTO_NEXUS_API_KEY	—	unset	Optional stdio authenticated identity

Operations

CLI commands

Command	Purpose
okto-nexus serve	Start MCP HTTP, REST, SSE, and dashboard
okto-nexus	Start MCP over stdio
okto-nexus tail	Operator NDJSON follower over the event service
okto-nexus admin prune	Enforce retention, optionally vacuum
okto-nexus admin issue-keys	Add keys to legacy keyless identities
okto-nexus admin export	Export a workspace replay stream as NDJSON

Use --help on every command for the full argument grammar.

Tail

okto-nexus tail \
  --project-root /absolute/path/to/project \
  --agent-id observer \
  --stream workspace \
  --from latest

tail applies per-agent event visibility. An optional --cursor-file belongs to that consumer only; corrupted checkpoints fail closed.

Retention

Start with a dry run:

okto-nexus admin prune \
  --project-root /absolute/path/to/project \
  --dry-run

Then execute:

okto-nexus admin prune \
  --project-root /absolute/path/to/project \
  --messages-keep-days 30 \
  --vacuum

Retention spans the whole shared store even though --project-root is validated as the command anchor. --vacuum is the only option that compacts freed pages on disk. There is no always-running coordination reaper; auto_prune_on_start is a bounded opportunistic pass.

Issue legacy keys

okto-nexus admin issue-keys \
  --project-root /absolute/path/to/project

This is additive and idempotent. Existing keys are never rotated. Newly issued plaintext keys are printed once.

Replay export

okto-nexus admin export \
  --project-root /absolute/path/to/project \
  --trace-id trc_... \
  --output nexus-events.ndjson

The first line is a manifest; subsequent lines are raw events ordered by event_id. CLI export is operator-shell access and remains available even when the REST replay flag is off.

Ephemeral monitor token

An authenticated agent can call poll_token_issue, give only the returned nxsept_... token and base URL to a read-only helper, renew it before expiry, and revoke it on teardown. The raw token is returned only on issue/renew.

Data model and migrations

The current schema contains 34 tables:

Area	Tables
Core coordination	schema_migrations, workspaces, agents, sessions, events, channels, messages, tasks, handoffs, artifacts, message_deliveries
Settings/security/catalogs	settings, permission_presets, tag_keys, tag_values, capability_names, ephemeral_poll_tokens
Search and memory	message_embeddings, memories, memory_embeddings
Governance/workflows	governance_policies, approvals, handoff_dependencies, policies, policy_versions, agent_policy_bindings, comm_presets, comm_preset_versions, agent_comm_binding, agent_groups, agent_group_members, guardrails, guardrail_versions, guardrail_assignments

Not every table is workspace-scoped: agents and catalogs are global, inbox deliveries are keyed by recipient identity, and bindings/control-plane records have their own ownership rules.

Migrations are embedded in the package and applied in order:

• 001–008: core schema, close metadata, handoff payload/result, presence, durable inbox deliveries, leases, and session secrets;
• 009–015: API keys, settings, permissions, embeddings, tags/scopes, capability catalog, and trace IDs;
• 016–021: governance, approvals, verification, dependencies, memory, and health/event indexes;
• 022–026: versioned attachable policies, communication presets, display colors, groups/guardrails, and ephemeral poll tokens.

Nexus refuses to run against an unsupported newer schema. Runtime SQLite databases and their WAL/SHM/journal sidecars are ignored and must not be committed.

Errors

The domain/MCP contract has a closed catalog of 29 canonical codes:

Area	Codes
Workspace	WORKSPACE_REQUIRED, WORKSPACE_UNRESOLVED, WORKSPACE_MISMATCH
Validation/identity	VALIDATION_ERROR, NOT_FOUND, NOT_OWNER, PERMISSION_DENIED
Catalog/control plane	TAG_IN_USE, CAPABILITY_IN_USE, POLICY_IN_USE, COMM_PRESET_IN_USE
Governance	POLICY_DENIED, QUOTA_EXCEEDED, GUARDRAIL_DENIED, CONFLICT
Dependencies/state	DEPENDENCY_NOT_FOUND, DEPENDENCY_NOT_MET, INVALID_TRANSITION, INVALID_STREAM
Handoffs	HANDOFF_ALREADY_CLAIMED, NOT_ELIGIBLE_TO_CLAIM
Content/path	CONTENT_TOO_LARGE, PATH_OUTSIDE_WORKSPACE
Infrastructure	CONFIG_ERROR, MIGRATION_ERROR, DB_ERROR, RENDER_ERROR
Compatibility/internal	MIGRATED, INTERNAL_ERROR

REST adapters also use transport-specific codes such as AUTH_FAILED, CROSS_ORIGIN_BLOCKED, INVALID_PARAM, INVALID_WINDOW, INVALID_SETTING, EMBEDDINGS_UNAVAILABLE, and INTERNAL.

Development

uv sync --extra dev
uv run pytest -q

For the complete HTTP/embedding environment:

uv sync --extra serve --extra dev
uv run pytest -q

Frontend:

cd frontend
npm ci
npm run build

The build writes packaged static assets under src/okto_nexus/adapters/inbound/http/static/.

Release checks:

uv lock --check
uv build --out-dir dist/release-0.1.3
uvx twine check \
  dist/release-0.1.3/okto_nexus-0.1.3-py3-none-any.whl \
  dist/release-0.1.3/okto_nexus-0.1.3.tar.gz

Publish only explicitly named current-version artifacts. The top-level dist/ may contain older builds.

Project layout

src/okto_nexus/
  adapters/
    inbound/
      cli/                  serve, tail, admin
      http/                 FastAPI, REST, SSE, packaged SPA
      mcp/                  server, resources, projections, 43/46 tools
    outbound/
      sqlite/               repositories and migrations adapter
      embedding/            optional semantic provider
      file/ sharedmd/       artifact and derived-view I/O
      telemetry/ tokenizer/ metrics support
  application/              use cases and ports
  domain/                   entities, routing, state machines, policies
  migrations/               001 through 026
  testing/                  reusable test/replay harnesses
frontend/                    React dashboard source
tests/                       unit, contract, integration, replay tests
docs/design/                 architecture and design records
pyproject.toml               package metadata and extras
uv.lock                      reproducible dependency lock

Troubleshooting

event_wait returns immediately

Pass timeout_seconds > 0. Omitted, null, and zero are snapshots by design.

An agent misses broadcasts

Check that it opened a session in the correct resolved workspace and continues to heartbeat. Read-only event/inbox checks do not advance presence.

A direct peer is missing from discovery

Authenticated discovery is filtered by communication reachability. Inspect the caller's outbound and the peer's inbound communication scopes/tags in the dashboard.

Capability or tag targeting fails

Create the capability/tag value in Registry first. Catalog validation is fail-closed.

Memory tools are absent

Set feature_memory=true and restart/reconnect. Unlike live behavior flags, this flag changes MCP tool registration.

Semantic search is unavailable

Use embedding_mode=stub or install the embeddings/serve extra and use embedding_mode=local. off intentionally disables search.

DB_ERROR reports a lock

If details.retryable=true, retry the same call after the competing writer commits. Avoid opening the runtime SQLite file with tools that hold long write transactions.

The hub says another server already owns the home

serve holds {home}/nexus.serve.lock and refuses a second server using that same home. Stop the other hub or choose a different --home; changing only --db-path does not change the lock scope.

Workspace path is rejected

Pass an existing absolute path. Nexus canonicalizes the real path before deriving the workspace ID and validating artifact containment.

A monitor cannot mutate state

That is expected for nxsept_ tokens. They are intentionally read-only and accepted only on the four monitor endpoints.

Cached docs appear stale

Call nexus_info and compare surface_revision and resource_versions before reusing cached MCP reference content.

Security and limitations

• Nexus is designed for local or controlled single-tenant coordination, not as a public multi-tenant broker.
• It does not terminate TLS. Put an authenticated TLS reverse proxy in front of a remote bind.
• The dashboard shell and public health/info/license assets remain public; data/control REST requires authentication outside loopback.
• API keys are hash-only at rest and shown once. Regeneration invalidates the old key immediately.
• Session secrets are stored in plaintext in the local SQLite database; anyone who can read that file is inside the session trust boundary.
• Channels are labels, not security boundaries.
• SQLite is the only built-in coordination store. There is no Redis, PostgreSQL, or cloud broker adapter.
• There is no always-running coordination scheduler/reaper. Expiry is checked opportunistically and retention runs manually or at startup when enabled.
• The HTTP server does use worker threads/tasks for operational needs such as blocking waits and telemetry; “no scheduler” does not mean “no threads.”
• Message durability is bounded by message retention and explicit reset.
• Memory is experimental and changes the MCP surface at startup.
• Artifact file references are confined to the canonical workspace.
• Avoid committing runtime databases, sidecars, metrics output, and local secrets to version control.

Future direction

Likely extension points are additional durable-store adapters, a push-backed waiter that removes internal sleep polling, stronger remote deployment packaging, and further generated documentation from the live MCP schemas. The delivered surface already includes permissions, catalogs, communication scopes, policies, guardrails, HITL, trace correlation, verified/DAG handoffs, memory, health, replay, ephemeral poll tokens, embeddings, metrics, REST, SSE, and the dashboard.

Release notes

0.1.3 — current

Maintenance, documentation, and repository-hygiene release. It does not change the MCP contract or database schema: surface revision remains 31 and the latest migration remains 026.

• Rewrote this README against the current CLI, transport/authentication model, dashboard, 43/46-tool surface, seven routing strategies, message retention, governance features, verification/DAG workflows, 34-table schema, 29-code error catalog, operations, testing, and limitations.
• Synchronized pyproject.toml and the root project entry in uv.lock at version 0.1.3, and aligned the package/dashboard license label with the addendum that is actually included in LICENSE.
• Removed tracked runtime SQLite databases and added ignore coverage for database files and journal/WAL/SHM sidecars.
• Verified release archives contain the dashboard and migrations without runtime SQLite databases or sidecars.

0.1.2

• Documentation-accuracy sweep at surface revision 31.
• Corrected pre-flight, monitoring, heartbeat, inbox, trace, policy, HITL, artifact-audience, and target-grammar documentation.
• Kept 12 deep reference resources versioned and reduced the resident cuttable surface to about 26.3k characters.
• Corrected the token-reduction gate to include experimental-surface growth.

0.1.1

• Hardened authenticated self-only identity/session rules and permission checks.
• Added permission-gated workspace paths, shared view, health, and memory.
• Added configurable aggregate metrics telemetry.

0.1.0

• Added ephemeral remote-monitor tokens and read-only monitor endpoints.
• Added attachable policies, communication presets, guardrail/group administration, enriched agent graph cards, and loopback trust hardening.
• Made memory a registration-time experimental MCP surface.

0.0.x

• Built the MCP reference-resource system, HTTP hub, live dashboard, inbox receipts, semantic search, monitoring guidance, and dashboard observability waves.

License

Copyright 2026 Okto Labs.

Okto Nexus is distributed under the Elastic License 2.0 together with the project's SaaS, competing-service, internal-use, and branding addendum. It permits internal and qualifying single-tenant use and prohibits the specified multi-tenant, white-label/OEM, competing, and large-scale internal-platform uses; applicable notices and attribution remain required.

Read the complete LICENSE before use or redistribution. It is also included in the source distribution and served by the running hub at GET /api/v1/license.