seldonframe/reelier
๐ ๐ ๐ ๐ช ๐ง - Record an agent's tool-call workflow once, replay it deterministically at 0 tokens, and diff runs to catch drift โ CI + snapshot tests for MCP tool-call workflows. npx -y reelier serve
Quick Install
{
"mcpServers": {
"seldonframe-reelier": {
"command": "npx",
"args": [
"-y",
"seldonframe-reelier"
]
}
}
}Using an AI coding agent (Claude Code, Cursor, etc.)? Copy a ready-made prompt that tells it to fetch the setup instructions and install this server for you.
Documentation Overview
Reelier
Agents make claims. Reelier writes receipts.
A dependency bump shouldn't silently break your agent. Reelier re-runs your recorded workflows against the new version at zero LLM cost and diffs them โ so you see exactly what changed before you merge.
Think of it as CI + snapshot tests for your agent's tool-call workflows.
Receipts on your agent PRs โ install and done
Agent-authored PRs (Dependabot, Claude, Codex, Cursor, โฆ) get a receipt comment in seconds: author, files changed, declared scope vs. what actually changed, sensitive paths flagged. No workflow file, no CLI, no config.
โ Install the Reelier receipts GitHub App โ free on public repos, forever.
Reelier receipt โ agent PR Author:
dependabot[bot]ยท Files changed: 2 (+119 โ41) Declared scope: none (add.reelier/scope.ymlto enable unexpected-write detection) Sensitive paths touched: โ 1 โpackage-lock.jsonProves scope and change, not correctness
A real receipt from Reelier's own repos โ see one live. Declare scope per agent in .reelier/scope.yml (or a reelier-scope block in the PR body) and the receipt reports unexpected writes. The receipt proves scope and change, never correctness or safety.
Why
AI agents are non-deterministic โ the same prompt, a different result every run โ and they'll claim they did the work whether they did or not. Reelier records the run that worked, replays it deterministically at $0, and writes a signed receipt that proves it. Point it at your existing CI in one workflow โ it adds a verifiable receipt, it doesn't replace your stack.
Measured on a real head-to-head benchmark, same task, same data (full method):
- 1,000 / 1,000 replays byte-identical
- ~50ร cheaper
- ~59ร faster
Install
npm i -g reelier && reelier init
# No Node install needed โ same commands via Docker:
docker run --rm ghcr.io/seldonframe/reelier --help
reelier init scans work you've already done (Claude Code, Codex, OpenClaw) into a real skill, or falls back to a zero-setup demo with a real receipt in under 60 seconds.
How to use it
reelier init # 60s: record โ compile โ replay โ your receipt
reelier run <name>.skill.md # replay deterministically โ 0 tokens (read-only by default)
reelier diff <name> # SAME or DRIFTED, per step โ exit 1 on drift
reelier push <name>.skill.md # sync receipts to your ledger (opt-in)
reelier ci # write a workflow: drift-CI + PR receipts, one command
- Record.
reelier mcp --wrap "<mcp server>"proxies your tools live, or pull a session viareelier scan/from-session, or run the guidedreelier init. - Compile.
reelier compileturns a trace into aSKILL.mdโ 0 LLM calls, minimal assertions, honest gaps printed as Open questions. - Replay.
reelier runreplays it at Level 0 โ no LLM, byte-identical, read-only by default (writes need--allow-writes). - Diff.
reelier diffreports SAME or DRIFTED per step, with the failing assertion as the why โ exit 1 on drift. - Log in.
reelier loginconnects this machine to Reelier Cloud with a device code in your browser โ or setREELIER_CLOUD_URL/REELIER_CLOUD_KEYfor CI and self-hosting. - Push. Every run is a receipt;
reelier pushoptionally syncs it to a ledger for a permalink and an embeddable verified-replay badge.
Already have an Agent Skill? Convert it โ your skill, minus the model:
reelier compile trace.jsonl --from-skill ./my-skill/SKILL.md
Three tests, one skill
| Test | Command | Answers |
|---|---|---|
| Determinism | reelier run <skill.md> | Does this still do what it did? |
| Recovery | reelier run <skill.md> --fail N | If this broke, would the skill notice and heal? |
| Drift | reelier run <skill.md> --wrap "<your mcp server>" | Has the world moved out from under this skill? |
Taxonomy due to Mads Hansen's review of the launch post. Full semantics for each test, including recovery injection and manifest guardrails: docs/REFERENCE.md.
Gate Dependabot / Renovate bump PRs
Dependabot and Renovate open the PR and run your test suite โ but neither knows what your agent actually does at runtime, so a dependency bump that silently changes a tool call's shape (a renamed field, a new default, a different error) sails through with green unit tests. This is the check they don't run.
Copy .github/workflows/reelier-bump-check.yml into your repo, point skill: at your own recorded .skill.md file(s), and it will: gate to PRs from dependabot[bot]/renovate[bot] (or a dependencies label), install the bumped dependency, replay your recorded skill live against it at --max-level 0 (0 tokens), and fail the check on the exact step that drifted.
This tests dependency and MCP-tool-call behavior โ it does not test model upgrades; --max-level 0 never calls an LLM. Full listing copy and setup: docs/marketplace-listing.md.
Prove it
A pushed receipt carries a ladder of independently-verifiable claims โ not one blanket "verified." Depending on what you turn on, it can be signed, timestamped, CI-attested, and carry cross-checkable provider request-ids. reelier verify recomputes every claim offline, and a claim you haven't enabled just renders as an honest gap, never a shamed one.
See a real one: reelier.com/r/HWBdmGob9KeHRqXi-OEaRD0z.
Full 8-rung ladder, what each rung does and doesn't prove: docs/REFERENCE.md.
Who it's for
- Solo dev / OSS maintainer โ a real regression test again; drift can't pass silently.
- Team shipping agent changes โ "it ran clean" becomes a checkable PR artifact, not a claim.
- Agency running agents for clients โ signed, timestamped proof-of-delivery a client can verify.
- Marketplace buyer or seller โ corroborated receipts are reviews that can't be astroturfed.
- Audit-facing ops โ a signed, CI-attested trail of every write, idempotency key included.
MIT, free forever (versions โค0.16.0 remain AGPL-3.0). Your data โ skills, traces, runs โ is specified in SPEC.md, so leaving is copying a folder.
Contributing: issues and PRs welcome โ SPEC.md is the source of truth for formats; fix the code, not the spec. npm test before a PR.
If Reelier saved you a re-run, star it โญ โ it's how other builders find it.