agentpause 0.4.0

Predictive scheduling for autonomous LLM agents: suspend gracefully before rate limits, resume without losing work.

agentpause

Predictive scheduling for autonomous LLM agents. Suspend an agent gracefully before it hits a provider rate limit, and resume it without redoing work.

The core works on any provider — cloud (OpenAI, Anthropic, Groq) or local — because it only serializes application-level state. True KV-cache warm start is an optional plugin for self-hosted runtimes (llama.cpp, vLLM).

Measured results (from the accompanying research)

Experiment	Result
Simulation, 300 runs/config	reactive baseline crashes up to 100% → predictive 0% (k=4), token waste −80%
Real provider (Groq free, 6K TPM)	multi-window task completed with zero 429 errors
vs LangGraph's MemorySaver (200 runs)	LangGraph: 7.8 × 429/run, 9,239 tokens wasted; predictive: 0 and 0
End-to-end A/B (thinking models, 4B/8B)	recovery 54×–93× faster; total task time −19%

Reproduce them yourself with a free key: python scripts/benchmark_groq.py. Live run (2026-07-08, Groq free tier, 12 steps, ~1k-token context, refill-aware chunked waiting, leveled windows):

	reactive baseline	agentpause
429 errors suffered	7	0
steps redone	7	0
tokens re-sent (waste)	12,840	0
telemetry overhead (pings)	0	259
wall-clock	82 s	86 s

Zero errors and zero waste at wall-clock parity: the sensor costs ~2% of what crashes waste (259 vs 12,840 tokens) — and waste is money on paid tiers.

Context slimming vs. answer quality (python scripts/quality_ab.py, live 2026-07-10, Groq llama-3.1-8b-instant): six facts planted early in a verbose conversation, same final quiz under three histories.

condition	prompt chars	facts recalled
A — full history	8,984	6/6
B — compact() (blind truncation)	4,370	0/6 — and the model invented plausible replacements
C — summarize_with() (one summary call)	3,608	6/6

A 2.2× larger run (--big, 19,145 chars — near the free tier's whole TPM window, the physical ceiling for a single call) repeated the pattern: A 6/6, B 0/6, C 6/6 at a third of the prompt.

The instructive failure is B's, and it is erratic: in one run it answered confidently with fabricated values (fake codename, fake budget, fake city); in the larger run it honestly declined. You cannot know in advance which failure you get — and the hallucinating one is the dangerous one. Blind truncation is an emergency exit (§8.6 overflow, no LLM available), not a strategy; semantic summarization recalled everything at a fraction of the prompt, earning its one extra call. A 20-step live stress test (2026-07-10) closed the loop: at the §8.6 wall the scheduler suspended, compacted the checkpoint offline, resumed slim, and completed 20/20 steps with zero 429s.

Facts vs. voice (python scripts/quality_ab.py, live 2026-07-20, Groq llama-3.1-8b-instant — the voice probe rides along on the same run, no extra flag needed): does shrinking a checkpoint also flatten the style it was written in, not just the facts inside it? A persona with two short verbal tics is planted in the same conversation as the six facts above:

condition	facts recalled	voice tics preserved
A — full history	6/6	1/2
B — compact() (blind truncation)	0/6	1/2
C — summarize_with() (one summary call)	6/6	0/2

Truncation and summarization fail in opposite, complementary ways: blind truncation keeps short, verbatim phrases intact (only long messages get cut) but loses facts scattered earlier in the history; summarization recovers the facts but rewrites everything in its own voice, so a persona's way of talking does not survive being summarized even when what it said does. If tone and persona consistency matter for your agent, compact() and summarize_with() are not interchangeable — pick per what you can't afford to lose.

Status: 0.4.0. Core scheduler, direct + LiteLLM + Anthropic adapters, LangGraph integration, multi-provider routing, multi-agent shared budgets, feature-based cost/latency estimation, task-completion forecast, checkpoint fork & cross-machine migration, an optional true-warm-start KV-cache plugin for llama.cpp, human attention as a budget, runnable examples, and a full test suite are all in place.

Install

pip install agentpause

Optional extras, only if you use them (the core has zero dependencies):

pip install "agentpause[litellm]"    # LiteLLM adapter (100+ providers)
pip install "agentpause[langgraph]"  # LangGraph adapter

Developing on the library itself (clone + editable install + tests):

git clone https://github.com/Champoleello/agentpause
cd agentpause
pip install -e ".[dev]"
pytest

Getting started

Step 1 — the smallest possible loop. backend is any callable messages -> (reply, tokens_used); telemetry is any callable () -> remaining_tokens. That's the entire contract — no framework required:

from agentpause import PredictiveScheduler

sched = PredictiveScheduler(backend=my_llm_call, telemetry=my_rate_limit_reader)

with sched.session("task-1") as s:      # resumes automatically if interrupted before
    for question in questions[s.step:]:  # skip steps finished before a suspend
        s.add_user(question)
        if s.should_suspend():           # predictive check, *before* the call
            s.checkpoint()
            break                        # stop cleanly; rerun to resume
        reply = s.call()
    else:
        s.complete()                     # task done: drop the checkpoint

Run it now, no API key needed: python examples/quickstart.py — it suspends mid-task on the first run and resumes cleanly the second time you run it.

Step 2 — the same three calls, wired into YOUR agent loop. Whatever framework you use (a hand-rolled ReAct loop, LangGraph, CrewAI, a plain while loop), the integration is always the same three calls in the same three places:

1. Before every LLM call, ask should_suspend() (or session.next_action() for the richer continue/wait/checkpoint answer). This is a local computation — no network call, no cost.
2. If it says stop, call checkpoint() and exit the process. Nothing else to do: state, messages, and idempotency keys are already on disk.
3. Re-running the same code with the same session id resumes automatically from the exact step — with sched.session(...) handles the restore.

Step 3 — pick the adapter for your provider, which supplies backend and telemetry for you instead of writing them by hand:

You use...	Adapter	Runnable example
LiteLLM (100+ providers)	adapters.litellm.LiteLLMAdapter	examples/litellm_groq.py
Direct HTTP, OpenAI-compatible (Groq, OpenAI, ...)	adapters.openai_compat.OpenAICompatAdapter	scripts/validate_provider.py
Direct Anthropic Messages API	adapters.anthropic.AnthropicAdapter	see "Real providers" below
LangGraph	adapters.langgraph.AgentPauseGuard	examples/langgraph_quickstart.py
A CrewAI/AutoGen/custom loop, no adapter yet	none — write backend/telemetry by hand as in Step 1	examples/quickstart.py

Details and full code for each adapter are in the sections right below; the ## Components table further down is the complete function/class reference for everything the library exposes.

Real providers via LiteLLM

The LiteLLM adapter supplies both callables for 100+ providers (OpenAI, Groq, Anthropic, local servers, ...), reading the budget from each response's rate-limit headers and refreshing stale readings with a tiny telemetry ping:

from agentpause import PredictiveScheduler
from agentpause.adapters.litellm import LiteLLMAdapter

adapter = LiteLLMAdapter(model="groq/llama-3.1-8b-instant")
sched = PredictiveScheduler(backend=adapter.backend, telemetry=adapter.telemetry)

Install with pip install -e ".[litellm]"; see examples/litellm_groq.py. To validate against your own provider (frontier models included): python scripts/validate_provider.py gpt-4o-mini.

Rate-limit headers by provider (defaults target the OpenAI-style names):

Provider	remaining tokens	remaining requests	reset
OpenAI	x-ratelimit-remaining-tokens	x-ratelimit-remaining-requests	x-ratelimit-reset-tokens (1s, 6m0s)
Groq	x-ratelimit-remaining-tokens	x-ratelimit-remaining-requests	x-ratelimit-reset-tokens (7.66s, 2m59.56s)
Anthropic	anthropic-ratelimit-tokens-remaining	anthropic-ratelimit-requests-remaining	RFC 3339 timestamp — set remaining_header= etc.

Header names differ? Override them: LiteLLMAdapter(model=..., remaining_header="...", requests_header="...", reset_header="...").

Self-hosted: ollama-gateway

Running Ollama locally behind martinobettucci/ollama-gateway (a self-hosted auth + quota proxy for Ollama)? It emits the same OpenAI/Groq-style x-ratelimit-* headers agentpause already reads, so it works out of the box through the direct adapter — no litellm, no special-casing. Confirmed live end-to-end (2026-07-20) against a real gateway instance: adapter.budget() correctly reads remaining_tokens, remaining_requests (decrementing per call), and reset_seconds — the one condition is that the API key has a quota configured (token cap and/or rate limit); a key with no quota set simply emits no rate-limit headers at all, which agentpause reports as a clear TelemetryError rather than a silent wrong answer:

from agentpause.adapters.openai_compat import OpenAICompatAdapter

adapter = OpenAICompatAdapter.for_model("ollama-gateway/llama3:8b")
# default base_url is http://127.0.0.1:8787/v1 (dev default); override for
# a custom port or a production HTTPS domain:
# OpenAICompatAdapter.for_model("ollama-gateway/llama3:8b",
#                                base_url="https://your-gateway-domain")

Beyond tokens: RPM and wait-vs-suspend

Telemetry can be richer than a token count. adapter.budget reports all three dimensions providers expose — remaining tokens (TPM), remaining requests (RPM), and seconds until the window resets — and unlocks the three-valued decision:

sched = PredictiveScheduler(backend=adapter.backend, telemetry=adapter.budget)

d = session.next_action()   # "continue" | "wait" | "checkpoint"

wait fires when the budget does not fit but the window resets within wait_threshold_s (default 15 s): a short in-place pause is cheaper than a full suspend/resume cycle. Exhausted requests (RPM = 0) block the call even with plenty of tokens left. Plain-int telemetry keeps working unchanged.

Async

Every entry point has an async twin — same rules, same guarantees, never blocks the event loop:

adapter = LiteLLMAdapter(model="groq/llama-3.1-8b-instant")
sched = PredictiveScheduler(backend=None, async_backend=adapter.abackend,
                            telemetry=adapter.telemetry)
reply = await session.acall()          # retry/backoff via asyncio.sleep
await guard.acheck(state["messages"])  # async LangGraph nodes

For sharper input estimates, wire the per-model tokenizer: PredictiveScheduler(..., count_tokens=adapter.count_tokens) (falls back to the ~4 chars/token heuristic if the tokenizer is unavailable).

When prediction fails anyway

Estimates are statistical — a 429 can still slip through. agentpause survives it instead of crashing:

• typed errors: everything derives from AgentPauseError (RateLimitHit, TelemetryError, CheckpointError, BackendError);
• retry with backoff: unexpected 429s are retried (provider retry-after honored, else exponential backoff — see RetryPolicy);
• hits are feedback: each one bumps safety_k up (capped at k_max), so the scheduler grows more cautious on workloads it underestimates;
• clean failure: a failed call leaves the session state untouched — no phantom steps, resumes stay consistent.

LangGraph integration

AgentPauseGuard adds the predictive gate to any LangGraph node — LangGraph persists reactively (after nodes), the guard pauses before the call that would hit the rate limit, via LangGraph's own interrupt() + checkpointer:

from agentpause.adapters.langgraph import AgentPauseGuard

guard = AgentPauseGuard(telemetry=adapter.telemetry)   # e.g. from LiteLLMAdapter

def agent_node(state):
    guard.check(state["messages"])       # pauses the graph here if needed
    reply = llm.invoke(state["messages"])
    guard.record(state["messages"], reply.usage_metadata["total_tokens"])
    ...

Resume the paused thread with graph.invoke(Command(resume=True), config). On resume the guard re-reads telemetry fresh — never from the checkpoint. Install with pip install -e ".[langgraph]"; see examples/langgraph_quickstart.py.

Scaling up: many providers, many agents, smarter estimates (v0.3)

The same predictive idea — read the budget first, act before the error — extends in three directions, and they compose:

from agentpause import BudgetRouter, MultiAgentCoordinator, FeatureEstimator
from agentpause.adapters.openai_compat import OpenAICompatAdapter
from agentpause.adapters.anthropic import AnthropicAdapter

# 1. Route each call to the provider with the most headroom (predictive
#    fallback: switch BEFORE the 429, not after). Providers in cooldown
#    after a real 429 are skipped until their window resets.
router = BudgetRouter(
    ("groq",   OpenAICompatAdapter.for_model("groq/llama-3.1-8b-instant")),
    ("claude", AnthropicAdapter("claude-haiku-4-5")),
)

# 2. Share ONE rate-limit window across a fleet: every granted call
#    reserves its predicted cost (estimate + k·σ) from the shared pool,
#    so agents can't overcommit the window together. Contention is
#    arbitrated by priority, then longest-waiting.
coord = MultiAgentCoordinator(telemetry=router.budget)
coord.register("researcher", priority=1)
coord.register("summarizer")

est = FeatureEstimator()                     # 3. learn cost from features,
est.set_context(tool="web_search")           #    not just context size

d = coord.request("researcher", estimated=est.estimate(1200),
                  sigma=est.sigma(fallback_estimate=1200))
if d.action == "continue":
    reply, used = router.backend(messages)   # router picks the provider
    coord.complete("researcher", actual_tokens=used)
    est.record(1200, used)

FeatureEstimator is a drop-in for the default estimator (PredictiveScheduler(estimator=FeatureEstimator())): a dependency-free ridge regression over features you declare (tool, model, temperature, …) that also learns per-step latency, feeding the optional time budget (PredictiveScheduler(time_budget_s=...)) — if the predicted step can't finish before the deadline, the answer is checkpoint, never wait (time, unlike tokens, does not refill).

Runnable demo without any key: python examples/fleet_quickstart.py (routing switch + predictive WAIT under a shared window, in 30 lines of loop).

Plan before you spend, fork your past, and survive a reboot (v0.4)

Four pieces that treat a suspended checkpoint as what it actually is: inert data you can inspect, clone, move, or accelerate.

from agentpause import HumanAttentionBudget, StateStore

# 1. FORECAST: before committing to a long run, simulate the REMAINING
#    steps against the live window (no network calls) and get an honest
#    estimate of tokens, money, waits/suspensions and wall-clock time.
forecast = session.forecast(steps_remaining=12)
print(forecast)  # flags context_wall / fits_time_budget if either fails

# 2. FORK: one suspended past, N independent futures. Clones are fully
#    independent (deep-copied messages, own idempotency namespace) but
#    inherit the parent's calibrated estimator (F9.3 symmetry).
store = StateStore(".agentpause")
store.fork("research-task", "research-task-cautious")
store.fork("research-task", "research-task-bold")

# 3. MIGRATE: the checkpoint directory IS the process image. Export it on
#    machine A, ship the bundle over any transport, resume on machine B at
#    the exact step.
bundle = store.export_bundle("research-task")
StateStore("/mnt/machine-b/.agentpause").import_bundle(bundle)

# 4. The human in the loop is a rate-limited resource too: N questions per
#    rolling hour, with a manual override for "I'm away".
attention = HumanAttentionBudget(max_asks=3, window_s=3600)
if not attention.ready():
    session.checkpoint()  # an absent human means suspend, not spin

For self-hosted llama.cpp, checkpoints can go further than logical state: KVStateStore wraps any StateStore and additionally saves/restores the model's KV-cache via /slots — a TRUE warm start (no re-prefill at all, not just no re-work). It degrades gracefully and automatically to a plain logical warm start whenever the accelerator can't be trusted: a model fingerprint mismatch, a missing blob, or a resume after import_bundle on a different machine (KV blobs are intentionally machine-local and never migrate).

from agentpause.llamacpp_kv import LlamaCppSlots, KVStateStore

kv_store = KVStateStore(StateStore(".agentpause"),
                        slots=LlamaCppSlots(), base_url="http://127.0.0.1:8080")
kv_store.save_with_kv(checkpoint)               # KV blob first, logical commit second
cp, info = kv_store.load_with_kv("research-task")
print(info)  # {"kv_restored": True, "n_restored": 4096} — or a graceful
             # {"kv_restored": False, "reason": "model_mismatch" | "kv_file_missing"}

Runnable demos without any key or server: python examples/migrate_fork.py (fork + migration story) and python examples/kv_llamacpp_demo.py (KV save/restore, model-change degradation, independent forked blobs, migration).

Why

Current agent frameworks persist state reactively: they checkpoint after a step completes and crash when the provider returns HTTP 429. agentpause adds a predictive layer that estimates the next step's cost, compares it against the remaining rate-limit budget, and suspends cleanly before the error — then resumes from the exact step.

This library is the engineering counterpart of the research preprint "A Resource-Aware Predictive Scheduler for Autonomous LLM Agents".

Components

Module	Role
PredictiveScheduler / Session	the high-level API: session(), should_suspend(), call(), checkpoint()
Estimator	predicts next-step token cost with a moving-average error correction (ε) and tracks σ
FeatureEstimator	drop-in replacement that learns cost and latency from declared features (tool, model, …) via dependency-free ridge regression
should_checkpoint / RiskModel	the suspension rule (remaining < estimated + k·σ) and a diagnostic risk score
Budget / decide	multi-dimensional telemetry (TPM, RPM, reset time, deadline) and the three-valued rule: continue / wait / checkpoint
StateStore / Checkpoint	atomic logical checkpointing with idempotency keys — works on any provider; compact() / summarize_with() shrink a suspended checkpoint offline
BudgetRouter	predictive multi-provider routing: reads every provider's budget first, routes to the most headroom, cools down 429'd providers
MultiAgentCoordinator	one shared rate-limit window across many agents: granted calls reserve their predicted cost; arbitrate() resolves contention by priority + fairness
ToolQuota	client-side sliding window for rate-limited tools that expose no headers
CircuitBreaker / FallbackBackend	reactive safety nets: fail fast on a broken provider, try the next one in order
adapters.litellm.LiteLLMAdapter	backend + telemetry for any LiteLLM-supported provider (headers → budget, stale reading → 1-token ping)
adapters.openai_compat.OpenAICompatAdapter	direct HTTP adapter for OpenAI-compatible APIs (Groq, OpenAI, …) — no litellm dependency
adapters.anthropic.AnthropicAdapter	direct adapter for the Anthropic Messages API, with cache_control prompt caching and measured cache_read/write_tokens
adapters.langgraph.AgentPauseGuard	predictive gate for LangGraph nodes: check() interrupts the graph before the fatal call, record() trains the estimator
Session.forecast()	pure, no-network simulation of the remaining steps: predicted tokens, money, waits/suspensions, wall-clock time; flags context_wall and fits_time_budget
Checkpoint.fork() / StateStore.fork()	one suspended past, N independent futures — deep-copied state, collision-free idempotency, inherited estimator calibration
StateStore.export_bundle() / import_bundle()	the checkpoint as a versioned, json-portable process image: suspend on one machine, resume on another at the exact step
HumanAttentionBudget	the person in the loop as a rate-limited Budget: N asks per rolling window + manual available()/away(until) override; composes with decide()
llamacpp_kv.LlamaCppSlots / KVStateStore	optional plugin: TRUE warm start for self-hosted llama.cpp via KV-cache save/restore, transactional, with automatic graceful degradation

Roadmap

• Core components + test suite
• PredictiveScheduler high-level API (session(), should_suspend(), call())
• Runnable quickstart example (no keys)
• LiteLLM adapter (works with any provider)
• LangGraph adapter (interrupt + checkpointer)
• Direct adapters (OpenAI-compatible, Anthropic with prompt caching)
• Predictive multi-provider routing (BudgetRouter)
• Shared budget across agents (MultiAgentCoordinator)
• Feature-based cost & latency estimator (FeatureEstimator)
• Task-completion forecast (session.forecast())
• Checkpoint fork & cross-machine migration
• Optional KV-cache plugin for llama.cpp (true warm start), incl. fork+KV
• Human attention as a rate-limited budget (HumanAttentionBudget)
• CrewAI / AutoGen / LlamaIndex adapters
• KV-cache plugin for vLLM

License

MIT