WorkBay Handoff MCP

Component of the workbay stack. You usually install workbay, not this package directly.

Portable MCP server for agent handoff state, review findings, exports, close checks, and lane-scoped worker/orchestrator coordination.

Scope

This package owns handoff state and related workflow primitives:

• task state, decisions, blockers, and next actions
• review findings and review runs
• generated CURRENT_TASK.json snapshots
• lane registration, lane activity, worker reports, and lane messages
• artifact indexing and derived metrics snapshots

It does not include unrelated repo-intel or UI helpers.

Runtime State

By default, runtime state lives under the workspace you point the CLI at:

• SQLite DB: .task-state/handoff.db
• exports: .task-state/exports/
• generated markdown: CURRENT_TASK.json

Override these with CLI flags or WORKBAY_HANDOFF_* environment variables. Legacy pre-rebrand names are still read for one release.

Tuning compaction thresholds

The compaction advisory (get_handoff_state(sections="identity").compaction_advisory) compares observed token and char totals against thresholds. The single source of truth for the canonical defaults is the compaction: block of docs/workbay/contracts/harness-protocol.yaml (threshold_tokens, threshold_chars); see that file for the current values and the rationale comment above them. Per-deployment overrides resolve with precedence env > overlay > contract, per knob, every call (no module-level cache):

1. Environment variables:

   • WORKBAY_HANDOFF_COMPACTION_THRESHOLD_TOKENS=<int>
   • WORKBAY_HANDOFF_COMPACTION_THRESHOLD_CHARS=<int>

2. .workbay-bootstrap.json at the workspace root, via the compaction.thresholds key (tokens and chars must be non-negative integers; the legacy .workbay-overlay.json name is still read as a fallback; the values below are illustrative overrides, not required values):

   {
     "compaction": {"thresholds": {"tokens": 90000, "chars": 360000}}
   }
   

   Either knob may be omitted; missing knobs fall through to env or contract.

3. Contract default in harness-protocol.yaml (single source of truth).

The advisory envelope reports the effective value at thresholds.{tokens,chars} and the resolving layer at thresholds_source.{tokens,chars} ("env" / "overlay" / "contract"). Invalid override values (non-int, negative) append a compaction_threshold_override_invalid: <source>=<key>=<value> warning to warnings and fall through to the next layer.

When the advisory says compaction is recommended, recording is still an explicit action: call compaction(operation="record", ...), run make compact-now, or let the compact-session Stop hook write the row. A successful record keeps compaction_id=<id> as the first operator-visible line and then prints receipt values in stable order:

compaction_id=C-WORKBAY-99-0001
tokens_saved_estimate=123
input_chars=4200
summary_chars=800
prose_residual_chars=200

load_session(include_context_refresh=True) can also return a soft same-session context_refresh packet for the latest compaction. Pass the returned dedupe_key back as last_injected_compaction_id to avoid injecting the same packet repeatedly. This refresh packet helps attention and grounding; it does not replace or disable the host harness's own context compaction.

Disabling WorkBay compaction

WorkBay unifies the runtime disable surface so the advisory short-circuit (compute_compaction_advisory) and the compact-session Stop hook are silenced together by a single resolver. Host-harness compaction (Claude Code's own /compact, Codex's internal summarization, etc.) is not affected — this disables WorkBay's tracker only. For the operator-facing comparison between WorkBay's compaction and the host harness's built-in compaction (and the note on what the compression-ratio benchmark actually measures), see docs/explainers/compaction-vs-default-harness-compaction.md.

Precedence (highest first):

1. WORKBAY_HANDOFF_COMPACTION_DISABLED env var (truthy). Legacy disable aliases are still honored for one release.
2. Task-scoped row in compaction_settings (when a task_ref is provided).
3. Workspace-default row in compaction_settings.
4. Otherwise: enabled.

Write the DB rows via any of these equivalent surfaces:

# Operator make wrappers (flagless, no YAML editing).
make compaction-disable                 # workspace default
make compaction-disable TASK=WORKBAY-99   # task-scoped
make compaction-enable  [TASK=...]
make compaction-status  [TASK=...]      # prints the resolved receipt

# CLI form (identical effect).
mcp-workbay-handoff compaction --operation disable [--task-ref WORKBAY-99]
mcp-workbay-handoff compaction --operation enable  [--task-ref WORKBAY-99]
mcp-workbay-handoff compaction --operation status  [--task-ref WORKBAY-99]

# MCP op form (callable from any harness; payload is a discriminated union).
compaction(operation="disable", task_ref="WORKBAY-99")
compaction(operation="enable",  task_ref="WORKBAY-99")
compaction(operation="status",  task_ref="WORKBAY-99")

Each call returns a CompactionStatusReceipt:

{"disabled": true, "source": "db", "env_override": false,
 "db_row": {"scope_kind": "workspace", "task_ref": null,
            "enabled": false, "updated_at": "...", "updated_by": "..."}}

When disabled=true, the advisory envelope carries disabled=true, disabled_source=<env|db> (threshold/floor logic skipped), the Stop hook logs compaction skipped: disabled (source=<env|db>), and the dashboard's Needs Attention rail prints compaction: disabled via <source>.

Doctor probe timeout budgets

mcp-workbay-handoff doctor bounds its subprocess health probes with a single overall deadline so a wedged probe cannot hang the health check:

• WORKBAY_DOCTOR_DEADLINE_SECONDS (default 30) — overall budget shared across the stdio-handshake and CLI startup probes. On exhaustion the timed-out probe is reported as ok=false with a remediation hint (the doctor still exits 0 in non-strict mode unless both probes fail).
• WORKBAY_HANDOFF_DOCTOR_STDIO_TIMEOUT (default 20) — per-probe ceiling for the stdio MCP handshake; always capped by the remaining overall deadline.
• WORKBAY_PRIVACY_UV_BUILD_TIMEOUT_SECONDS (default 120) — bounds the uv build step of the shipped-artifact privacy gate (scripts/check_shipped_privacy.py); a wedged build fails the gate with a clear message instead of hanging.

Non-positive or unparseable values fall back to the defaults, so a bad env can never disable a bound.

Installation

From PyPI (recommended)

pip install mcp-workbay-handoff
# or, as an isolated tool:
uv tool install mcp-workbay-handoff
# or, ad-hoc without installing (pin a release for reproducibility):
uvx mcp-workbay-handoff@0.11.1 --workspace-root /path/to/workspace serve-stdio

From the monorepo source tree (development)

From this package root inside workbay:

cd packages/mcp-workbay-handoff
python -m pip install -e ".[dev]"

Development

All package-local development commands are intended to run from the package root:

make lint-handoff
make fix-lint-handoff
make format-handoff
make mypy-handoff
make test-handoff
make check-handoff

Prefer the package-local Make targets when running checks from editors or agent sessions. Workspace-level interpreter discovery can point at a minimal environment that lacks this package's dev extras such as pytest, while make test-handoff and make check-handoff keep execution anchored to the package root and honor PYTHON=/path/to/python3 overrides when you need to pin a specific interpreter.

The Makefile automatically adds a sibling ../workbay-codex-bridge/src to PYTHONPATH when that checkout exists. In a fully extracted repo, that fallback is unnecessary once dependencies are installed normally.

Direct commands also work:

PYTHONPATH=src python -m ruff check src tests
PYTHONPATH=src python -m mypy src
PYTHONPATH=src python -m pytest tests -q

Python API

The package can be used directly as a library — this is the primary fallback when MCP tool calls are unavailable.

Always import from the package root (workbay_handoff_mcp), never from submodules like .config, .decisions, or .core. Submodules are internal and may change.

from pathlib import Path
from workbay_handoff_mcp import (
    RuntimeConfig,
    configure_runtime,
    get_handoff_state,
    search_handoff,
  validate_decision_id,
    record_event,
    review_findings,
    list_review_findings,
    set_handoff_state,
    update_task_status,
    get_verified_tests,
    render_handoff,
    record_file_touch,
    get_touched_files,
)

# Configure runtime before any read/write call
configure_runtime(RuntimeConfig.for_repo(Path("/path/to/workspace")))

# Read state
state = get_handoff_state(sections="identity")

# Search decisions
results = search_handoff(queries=["slice_complete"], record_types=["decision"], limit=5)

# Preflight a slice-complete decision id before writing
preflight = validate_decision_id(
  decision="codex_slice_complete_plan0004_contract-pinning-and-docs",
  decision_kind="slice_complete",
)

# List open findings
findings = list_review_findings(status="open")

Without installation (monorepo source tree):

PYTHONPATH=packages/mcp-workbay-handoff/src python3 -c "
from pathlib import Path
from workbay_handoff_mcp import RuntimeConfig, configure_runtime, get_handoff_state
configure_runtime(RuntimeConfig.for_repo(Path('.')))
state = get_handoff_state(sections='identity')
print(state['data']['active']['task_ref'])
"

Compaction Advisory

get_handoff_state(sections="identity") exposes the canonical compaction advisory at data.compaction_advisory, with a mirrored boolean at data.compaction_recommended (key configurable via compaction.advisory_field in docs/workbay/contracts/harness-protocol.yaml). The same envelope is mirrored by load_session, and the workspace-summary CURRENT_TASK.json carries it at active.compaction_advisory (no data wrapper — CURRENT_TASK.json is the projection file itself, not an MCP tool envelope).

state = get_handoff_state(sections="identity")
advisory = state["data"]["compaction_advisory"]
if advisory["recommended"]:
    # Schedule a compaction; thresholds + observed totals + transcript path
    # are documented under the advisory envelope.
    ...

Cold-start consumers MUST read advisory state from this surface rather than recomputing token/character totals locally — the evaluator owns contract loading, transcript discovery, and harness detection.

CLI Usage

Run the MCP server over stdio:

mcp-workbay-handoff --workspace-root /path/to/workspace serve-stdio

Run the MCP server over HTTP:

mcp-workbay-handoff --workspace-root /path/to/workspace serve-http

FastMCP's current HTTP defaults are:

• host: 127.0.0.1
• port: 8000
• path: /mcp

Useful CLI checks:

mcp-workbay-handoff --workspace-root /path/to/workspace doctor
mcp-workbay-handoff --workspace-root /path/to/workspace state
mcp-workbay-handoff --workspace-root /path/to/workspace validate --kind decision-id --decision codex_slice_complete_plan0004_contract-pinning-and-docs --decision-kind slice_complete
mcp-workbay-handoff --workspace-root /path/to/workspace review-findings --operation list
mcp-workbay-handoff --workspace-root /path/to/workspace handoff-close-check

Slice-complete Decision IDs

Do not hard-code the slice-complete regex in client prompts or scripts. Treat get_handoff_state(sections="identity").data.limits.write.slice_complete_decision_id as the authoritative registry, and use validate_decision_id(decision=..., decision_kind="slice_complete") for side-effect-free preflight when composing ids outside close_slice(author_tag=..., work_ref=..., slug=...).

Valid: cdx_slice_complete_plan0004_contract_pinning_and_docs

Invalid: cdx_slice_complete_plan0004_contract-pinning-and-docs

Review Intake

Preferred path when workbay-orchestrator-mcp is available:

1. get_latest_slice_review_packet
2. get_review_findings_summary or review_findings --operation list as needed

Handoff-only fallback:

1. load_session
2. search_handoff(queries=["slice_complete"], record_types=["decision"], limit=1)
3. get_verified_tests(task_ref=..., commit_sha=...)
4. review_findings(review={"operation":"list","status":"open"})

Use the MCP read surfaces above before inspecting .task-state/handoff.db directly. Drop to raw SQLite or filesystem inspection only when the required MCP tool is unavailable or when you are debugging MCP transport or serialization failures.

Source-tree execution without installation:

PYTHONPATH=src python -m workbay_handoff_mcp --workspace-root /path/to/workspace serve-stdio

Token-Efficient Usage

The v2 envelope is already compact, but callers still save the most tokens by shaping read responses deliberately:

• Prefer named read_profile= over hand-rolled sections=/top_n_* in routine paths. Profiles: identity, hot_summary, review_packet, open_items, full_debug. Profiles bundle a stable shape and surface data.read_shape.applied_profile for verification.
• Pair read_profile= with response_budget_bytes= in production retry loops. The Layer-2 budget planner reduces detail level, halves top_n_*, and drops optional sections before heavy rows materialize, so a budgeted call returns within a single round trip. The default policy is auto_summary when a budget is set; pass budget_policy="fail" to receive data.read_budget.retry_with instead of an over-budget payload.
• Use get_handoff_state(read_profile="identity") (or the legacy sections="identity") for routine task checks instead of a full state fetch.
• Use detail="summary" on read surfaces such as get_handoff_state, load_session, review_findings, search_handoff, and artifacts when truncated text is acceptable.
• Use top_n_*, limit=, and fields= to cap read size instead of trimming large payloads client-side. load_session accepts top_n_touched_files (default 20, max 200) to bound the additive touched_files list.
• Read from the canonical data block — result["data"]["active"] etc. The legacy top-level mirror was removed in 0.3.0 and never returns.

Package-local guidance and examples live in docs/guides/token-efficient-usage.md.

Wire format note (≥0.3.0)

Starting in mcp-workbay-handoff 0.3.0, MCP tool responses are native JSON objects on the wire, not JSON strings inside structured_content.result. Every handler is annotated -> dict and returns a real dict via _envelope(); FastMCP serialises it once. If you previously did json.loads(handoff_tool(...)) to parse a JSON string return value, drop the json.loads — the call returns a dict directly. If you previously read result.content[0].text from the MCP wire payload and parsed it, read result.structured_content directly instead.

The envelope field set is unchanged (ok, schema_version, tool, scope, data, mutation, artifacts, warnings, task_ref) and schema_version stays at 2. Only the wire-encoding moved from JSON-string-inside-JSON to a native nested object. See CHANGELOG.md for the full migration notice.

Client Adapter Shape

Installed console-script adapter (resolves whatever version is currently installed):

{
  "name": "workbay-handoff-mcp",
  "command": "mcp-workbay-handoff",
  "args": ["--workspace-root", "/path/to/workspace", "serve-stdio"]
}

Pinned via uvx (recommended for consumers — reproducible across machines without a global install):

{
  "name": "workbay-handoff-mcp",
  "command": "uvx",
  "args": [
    "mcp-workbay-handoff@0.11.1",
    "--workspace-root",
    "/path/to/workspace",
    "serve-stdio"
  ]
}

Source checkout adapter:

{
  "name": "workbay-handoff-mcp",
  "command": "python3",
  "args": [
    "-m",
    "workbay_handoff_mcp",
    "--workspace-root",
    "/path/to/workspace",
    "serve-stdio"
  ],
  "cwd": "/path/to/mcp-workbay-handoff",
  "env": {
    "PYTHONPATH": "/path/to/mcp-workbay-handoff/src"
  }
}

Version pinning

Consumer configs should pin the server version they were validated against so that client-adapter contract drift is visible at config-review time rather than at runtime. The installed console-script adapter resolves whatever release is currently installed; the uvx and source-checkout variants above pin a known release.

To verify the version of the server actually being launched:

mcp-workbay-handoff --version
# mcp-workbay-handoff 0.11.0

The same value is exposed as a top-level field in run_doctor output so adapters can introspect it via the MCP surface:

{
  "ok": true,
  "version": "0.11.0",
  "workspace_root": "/path/to/workspace",
  "...": "..."
}

Tool Surface

mcp-workbay-handoff now exposes a single unified MCP surface.

Legacy --tool-profile all|core|extended inputs are still accepted for compatibility, but they all expose the same tool set:

mcp-workbay-handoff --workspace-root /path/to/workspace --tool-profile core serve-stdio

Unified surface

CLI name	MCP tool
state	get_handoff_state
set	set_handoff_state (pass --status-only for status-only updates that replace the legacy update_task_status)
validate	validate (--kind decision_id|write; replaces the legacy validate-decision-id and validate-write subcommands)
event	record_event
next-actions	next_actions
review-findings	review_findings
review-runs	review_runs
integrity-check	integrity_check (--kind working_tree|post_merge|close; replaces the legacy working-tree-integrity-check, post-merge-integrity-check, and handoff-close-check subcommands)
render-handoff	render_handoff (kind=current_task/dashboard)
(no CLI)	load_session
(no CLI)	close_slice
audit-decisions	audit_decision_ids
export	export_handoff_state
import	import_handoff_state
archive	archive (--operation archive|gc|get; replaces the legacy archive-task-state, tasks-gc, and get-archived-task subcommands)
artifacts	artifacts (typed --operation selects record, search, get, or purge for indexed artifact rows)
touched-files	touched_files (--operation record|list; replaces the legacy record-file-touch and get-touched-files subcommands)
compaction	compaction (--operation record|get|get_latest; replaces the legacy compact-session, get-compaction, and get-latest-compaction subcommands)
handoff-search	search_handoff
handoff-rows	list_handoff_rows
get-verified-tests	get_verified_tests

record_event uses a typed event payload with event_kind="decision" | "test_result" | "blocker" so each variant keeps its own required fields. next_actions uses operation="list" | "add" | "update" | "complete" | "skip". review_findings uses operation="record" | "batch_record" | "update" | "list". review_runs uses operation="record" | "list" | "coverage".

Branch/worktree drift is surfaced through warnings on write responses. If you set WORKBAY_HANDOFF_ENFORCE_BRANCH=1, branch mismatches against the active task's target_branch fail before mutation on enforceable branches. Direct Python callers see BranchMismatchError; MCP clients receive the standard v2 error envelope with data.expected_branch and data.actual_branch.

CLI-only extras (not part of MCP registry): artifact-list, artifact-terms.

Surface classes:

• action: mutates canonical state; do not blind-retry
• query: read-only inspection of canonical state; usually safe to retry
• generator: derived output such as close checks, markdown renders, and metrics summaries

Troubleshooting

The fastest first check is still:

mcp-workbay-handoff --workspace-root /path/to/workspace doctor

If startup succeeds but calls fail, check the workspace paths first: --workspace-root, --state-dir, --current-task-path, and --exports-dir must all point at the same workspace state.