Aperture MCP server

<!-- mcp-name: io.github.jaysinailabs/aperture-mcp -->

Aperture

A commitment tripwire &nbsp;·&nbsp; git hook · CI · CLI · MCP

Did an agent quietly drop a commitment from your spec — and no one noticed?

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AI agents now rewrite the documents that govern your work — specs, plans, ADRs, charters, AGENTS.md files. Somewhere in the edit, a constraint you set earlier can quietly disappear.

Aperture is a commitment tripwire. You name the commitments you care about; it flags — word for word — when one of them vanishes between two versions of a decision document.

Catching "a commitment silently vanished" is a tripwire job: it should fire on an event, deterministically, without asking permission. So Aperture ships that check on the surface that fits it best first — a git pre-commit hook / CI check that runs with no LLM, offline — and also as a CLI and an MCP server for agents to call mid-task. MCP is one adapter, not the whole product.

A signal, not a judge. It trips; you investigate.

Opt-in · runs locally · never trains on your data.

What it is (and what it is not)

Aperture compares two text states of the same decision — an earlier version and a later one — and surfaces a narrow, specific kind of decision drift: when a tracked commitment’s exact text disappeared. One engine, several surfaces:

model in the loop, and blocks (or warns) automatically.

• git pre-commit hook / CI check — the deterministic form. Fires on the commit / PR event with no

runs if the agent chooses to call it — but useful mid-task).

• aperture check CLI — run the same check by hand between any two git states.
• MCP server — so an agent can call the check while it edits (weaker as a tripwire, since it only

What the engine does and doesn’t do:

from version B — across commits, sessions, or authors. It returns a structured, comparable result with its own blind spots written on the label.

• ✅ It does: flag when a commitment you listed verbatim is present in version A and gone

misses a commitment that was reworded / softened / paraphrased (it looks dropped-free even though the promise weakened); it declines/abstains on a commitment that was merely translated (it can’t compare verbatim across scripts, so it returns degraded rather than false-flag); and it can still false-flag a commitment that was merely reformatted (the words moved, the meaning didn’t). It does not rank options, score quality, or tell you a change was wrong. That judgment stays with you. Moving to the deterministic git-hook makes the check fire reliably — it does not widen what it can see. Same narrow, verbatim signal.

• ❌ It does not: understand meaning. It matches text as a case-insensitive substring, so it

If you want one sentence: Aperture is grep for vanished commitments, wired to fire on commit — and honest enough to admit what it can’t see.

Quickstart (≈2 minutes)

pip install aperture-mcp   # installs the `aperture` CLI + the MCP server (wire the CLI as a git hook — see below)

The PyPI package is named aperture-mcp because the bare name aperture was already taken on

PyPI. The -mcp suffix is a historical package-name artifact — the product is Aperture, and

MCP is only one of its surfaces. One pip install gives you all three below.

1. The deterministic tripwire — git pre-commit hook / CI (no LLM, offline)

Shortened. The full README is on GitHub.