Selvedge

Long-term memory for AI-coded codebases. A git blame for AI agents — but for the why, not just which line which model touched. Captured live, by the agent, as the change happens.

Selvedge is a local MCP server. AI coding agents (Claude Code, Cursor, Copilot) call it as they work to log structured change events with reasoning. Your data stays in a SQLite file under .selvedge/ next to your code.

Six months ago, your AI agent added a column called user_tier_v2. You don't know why. git blame points to a commit from claude-code with a generated message that says "Update schema." The session that made the change is long gone — and so is the prompt that produced it.

With Selvedge, you run this instead:

$ selvedge blame user_tier_v2

  user_tier_v2
  Changed     2025-10-14 09:31:02
  Agent       claude-code
  Commit      3e7a991
  Reasoning   User asked to add a grandfathering flag for legacy free-tier
              users during the pricing migration. Stores the original tier
              so we can backfill discounts without touching billing history.

That reasoning was captured by the agent in the moment — written into Selvedge from the same context that produced the change. Not inferred from the diff afterward by a second LLM. Not a hand-typed commit message.

Who Selvedge is for

Selvedge has two audiences. Same tool, same pip install, same SQLite file under .selvedge/. Different scale of pain.

Teams running long-term, AI-coded codebases. When the project is big enough that you (or someone else) will touch it again in six months, twelve months, three years — but most of it was written by an agent whose context evaporated the day each PR shipped. git blame tells you what changed. Selvedge tells you why — even after the agent session, the prompt template, the developer who asked for it, and the model version are all long gone. This is the original use case: production codebases, schema decisions, migrations, dependency changes that need an audit trail that survives turnover.

Solo developers using Claude Code on everyday projects. Side projects, weekend builds, the small internal tool you keep poking at. You don't need enterprise governance — you just need to remember why you (or your agent) did the thing you did yesterday, last week, last sprint. Run selvedge init once. Add four lines to your CLAUDE.md. From then on, selvedge blame is muscle memory — a way to talk to your past self when your past self was an LLM.

If you've ever come back to your own AI-built project and thought "what was this for again?", Selvedge is the missing piece.

The problem

Human-written code leaks intent everywhere — commit messages, PR descriptions, inline comments, the Slack thread that preceded it. AI-written code doesn't. The agent has perfect clarity about why it made each decision, but that context lives in the prompt and evaporates when the conversation ends.

Six months later, your team is debugging a schema decision with no trail. git blame tells you what changed and when. It can't tell you why.

Selvedge captures the why — live, by the agent itself, as the change is made. The diff is git's job. The why is Selvedge's.

What's new in v0.3.9.3

Fixes a broken install, and lands a full code-quality pass. mcp 2.0.0 (released 2026-07-28) removed mcp.server.fastmcp, and Selvedge declared mcp>=1.0.0 with no upper bound — so any pip install selvedge after that date pulled 2.0.0 and selvedge-server failed at import. This release pins the dependency. If your server stopped starting, this is why — upgrade.

It ships alongside a review that put nine independent passes over the codebase and then tried to disprove every finding before acting on it. Seventeen confirmed defects fixed. The ones you would actually have noticed:

• The enforcement hook stopped blocking things it shouldn't. Reading a tracked file — cat, git diff, pytest, ruff check — was blocked, and the remediation the error message told you to run was blocked by the same gate, so there was no way out from the CLI. Two more paths fed the same false blocks: a commented-out line of SQL counted as a real deletion, and any commit message merely containing the word "revert" marked every file it touched as reverted.
• Lookups got fast at scale. The main entity read was scanning every row — measured 7.4 ms → 0.35 ms at 100k events, and the hook had been taking seconds on large stores.
• selvedge setup can no longer delete parts of your CLAUDE.md, an interrupted backup can no longer destroy your last good one, and upgrading while two Selvedge processes are running no longer crashes with an error that looked like database corruption.

Tests went 739 → 826. No schema change and no tool-surface change, so this is drop-in for anyone on 0.3.9.x.

What's new in v0.3.9.2

The Claude Code plugin is first-class now — not scaffolding. Two commands, no prior pip install: the plugin fetches the server itself.

/plugin marketplace add masondelan/selvedge
/plugin install selvedge@selvedge

One install carries the whole agent-facing surface. The MCP server starts through a launcher that tries an existing install, then uvx, then pipx — so a fresh machine needs nothing preinstalled, and anyone who already has Selvedge on their PATH keeps their exact version. Alongside the server, the install ships a skill that tells the agent when to reach for the tools (before editing a tracked entity, after any substantive change), the PreToolUse enforcement hook wired in by default, and four slash commands — /selvedge:status, /selvedge:blame, /selvedge:history, /selvedge:prior-attempts. The skill's text is generated from the same block selvedge prompt installs, so the plugin and the hand-written prompt can't drift. No store, schema, or tool-surface change — this is packaging, not new behavior. Drop-in for anyone on 0.3.9.x.

Where Selvedge fits

AI agents call Selvedge as they work. Selvedge captures the why into a durable, queryable store and emits it back out — as Agent Trace records for cross-tool readers, as observability metadata that links into Sentry/Datadog stack traces, and as compliance artifacts for SOC 2 and EU AI Act audits.

Selvedge does not replace git (line-level what/when), PR review tools (review-time quality), agent observability (LLM call traces), or general-purpose code-host AI features. It sits between them — the provenance-as-first-class-citizen layer that everything else references.

How Selvedge compares

There's a fast-growing "git blame for AI agents" category. Here's where Selvedge fits — and where it deliberately doesn't.

Why "captured live" matters. AgentDiff and Origin generate reasoning after the change is made, by feeding the diff back to a second LLM call. Selvedge's reasoning is the agent's own intent, written from the same context window that produced the change — no inference, no hallucinated explanations, and an empty reasoning field is itself a useful signal (the agent didn't have one).

Why "entity-level" matters. Most tools attribute lines. Selvedge attributes things you actually search for: users.email, env/STRIPE_SECRET_KEY, api/v1/checkout, deps/stripe. The first question after git blame is usually "what's the history of this column", not "what's the history of lines 40–48 of users.py".

Why "changesets" matter. A Stripe billing rollout touches the users table, two new env vars, three new API routes, one dependency, and four functions across the codebase. Tag every event with changeset:add-stripe-billing and you can pull the entire scope back later — even if the original PR was broken into eight smaller ones over a month.

Selvedge ↔ Agent Trace. Agent Trace (Cursor + Cognition AI, RFC Jan 2026, backed by Cloudflare, Vercel, Google Jules, Amp, OpenCode, and git-ai) is an emerging open standard for AI code attribution traces. Selvedge isn't a competitor to it — it's a compatible producer. As of v0.3.9, selvedge export --format agent-trace emits Agent Trace v0.1.0 records (and selvedge import --format agent-trace reads them back); the mapping is in docs/agent-trace-interop.md. Agent Trace is the wire format. Selvedge is the live capture + query layer that emits it.

Quickstart

Claude Code — install the plugin (recommended)

Two commands, inside Claude Code. No prior pip install — the plugin bootstraps the server itself via uvx (or pipx):

/plugin marketplace add masondelan/selvedge
/plugin install selvedge@selvedge

That's the whole agent-facing surface in one step:

• the MCP server — 8 tools (log_change, prior_attempts, blame, diff, history, changeset, search, stale_decisions);
• a skill that tells the agent when to call them — before editing a tracked entity, after any substantive change;
• the PreToolUse enforcement hook — schema/migration edits are blocked until prior_attempts has been checked this session, with the prior reasoning in the block message;
• slash commands — /selvedge:status, /selvedge:blame <entity>, /selvedge:history, /selvedge:prior-attempts <entity>.

The store (.selvedge/selvedge.db) creates itself on the first logged change. Two optional extras stay CLI-side: the post-commit hook that stamps each event with its commit hash (selvedge install-hook), and — if you want the selvedge command on your own shell PATH — pip install selvedge, whi

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