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.

Related MCP server: gitwhy-mcp

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 v0.3.9.1

The dev.to feedback release. Five improvements publicly promised in the comment threads of the launch post, all landed. Append-only store and zero-LLM core, unchanged. Drop-in upgrade for anyone on 0.3.9 (the v4 migration is metadata-only, instant at any size).

Reverted is no longer a permanent ban. A reverted decision can become correct again — so re-open it explicitly, without rewriting history:

selvedge supersede payments.card_token \
  --reasoning "Provider now vaults card data — the PCI constraint is gone."

prior_attempts / blame / diff then read the full trail — tried → reverted → re-opened — with a clear current-status line. Decisions can now also carry a queryable constraint (the principle that drove them) and a stale_when condition; when a later change event matches the condition, stale_decisions flags the decision "review suggested" (surfacing only — no automatic un-retiring, ever).

The prior_attempts check is now enforceable. selvedge setup installs a Claude Code PreToolUse hook that blocks schema/migration edits until prior_attempts has been checked this session — and puts the prior reasoning in the block message, so the agent gets the skipped context for free. Fail-open by contract (a miss or error always allows), --dry-run and SELVEDGE_HOOK_DISABLE=1 included.

Your pre-Selvedge reverts count too. selvedge import --from-git walks git history (revert-message commits + file deletions) and seeds change_type="revert" events, idempotently — so the mistakes your repo already made once gate the hook and prior_attempts from day one.

And recall that survives renames (optional):

pip install "selvedge[semantic]" && selvedge index
selvedge prior-attempts --fuzzy "tokenized payment credentials"
# finds the users.card_token revert even though you asked about payment tokens

Local static embeddings (model2vec, ~30 MB, no torch), clearly-labeled fuzzy matches, substring fallback when the extra isn't installed. Core never imports it. Full details in CHANGELOG.md.

What's new in v0.3.9

Agent Trace export — Selvedge is a compatible producer. selvedge export --format agent-trace emits Agent Trace v0.1.0 records — the open AI code-attribution wire format from Cursor + Cognition AI — so your captured history travels to any tool that reads the standard. Selvedge's reasoning and entity-level provenance ride along in each record's metadata under the dev.selvedge namespace. Drop-in upgrade for anyone on 0.3.8.

selvedge export --format agent-trace -o trace.json            # one record per event
selvedge export --format agent-trace --ndjson -o trace.ndjson # stream, one per line
selvedge export --format agent-trace --collapse-by-session    # merge a session into one record
selvedge import trace.json --format agent-trace               # round-trip back in

It's opt-in and additive — nothing about the native model, the 8 MCP tools, or local SQLite changes. Entity-level events (a column, an env var, a dependency) have no line range, so Selvedge marks them metadata.dev.selvedge.range_unknown: true rather than fabricating one — an honest fidelity signal. This was planned for v0.4.0; only the exporter moved forward (Postgres + the tool rename remain the v0.4.0 markers; HTTP + auth ships in v0.4.1). Full mapping in docs/agent-trace-interop.md.

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

pip install selvedge
cd your-project
selvedge setup

That's it. selvedge setup is an interactive wizard: it detects which AI tools you have (Claude Code, Cursor, Copilot), writes the MCP entry into each one's config, drops the canonical agent-instructions block into your project's prompt file (CLAUDE.md / .cursorrules / copilot-instructions.md), installs the PreToolUse enforcement hook into .claude/settings.json (Claude Code only — blocks schema/migration edits until prior_attempts has been checked; --skip-enforcement-hook to opt out), runs selvedge init, and installs the post-commit hook. Every modified file gets a .bak written next to it before any change reaches disk. Re-running is a no-op.

For CI bootstrap or devcontainer.json postCreateCommand:

selvedge setup --non-interactive --yes

Claude Code plugin marketplace (alternative)

If you're a Claude Code user and want to install Selvedge through the official plugin marketplace flow, run these inside Claude Code after pip install selvedge:

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

The plugin system wires the MCP server into Claude Code, but it does not install the Python package for you — pip install selvedge first, otherwise the selvedge-server command won't exist on your PATH and the plugin can't start. For the full setup (post-commit hook, project CLAUDE.md instructions block, etc.), selvedge setup is still the recommended path; the plugin marketplace install is just the lightweight Claude-Code-only entry point.

Verify the wiring — open a second terminal in the same project:

selvedge watch

Make any change in your AI tool — add a column, rename a function, add an env var. selvedge watch should print the new event within a second of the agent calling log_change. If nothing arrives, run selvedge doctor for a single-command health check that tells you which step is silently broken.

Query your history:

selvedge status                        # recent activity + missing-commit count
selvedge diff users                    # all changes to the users table
selvedge diff users.email              # changes to a specific column
selvedge blame payments.amount         # what changed last and why
selvedge history --since 30d           # last 30 days of changes
selvedge history --since 15m           # last 15 minutes ('m' = minutes)
selvedge changeset add-stripe-billing  # all events for a feature/task
selvedge search "stripe"               # full-text search
selvedge stats                         # log_change coverage report (per-agent)
selvedge import migrations/            # backfill from migration files
selvedge export --format csv           # dump history to CSV

If you don't want to run the wizard, the four manual steps it automates:

1. Initialize in your project

cd your-project
selvedge init

2. Register the MCP server

Selvedge is a standard stdio MCP server, so it works with any MCP client — Claude Code, Cursor, Windsurf, Codex CLI, Gemini CLI, and more. See Works with any MCP client for the exact config per client. For Claude Code:

claude mcp add selvedge -- selvedge-server

3. Tell your agent to use it

selvedge prompt --install CLAUDE.md

Point --install at whichever prompt file your client reads — the block itself is identical across clients:

This installs the canonical agent-instructions block, sentinel-bracketed (<!-- selvedge:start --> / <!-- selvedge:end -->) so future --install calls update the bracketed region without disturbing anything else in the file. Or pipe it:

selvedge prompt | tee -a CLAUDE.md

Prefer to copy-paste? The same block is one click away on the website: selvedge.sh/prompt-block — with a copy button and notes on what your agent does with it.

4. Install the post-commit hook

selvedge install-hook

That's the same four steps the wizard runs.

Works with any MCP client

Selvedge is a standard stdio MCP server — its launch command is selvedge-server, put on your PATH by pip install selvedge. Any MCP-capable client can run it. Pick yours:

claude mcp add selvedge -- selvedge-server

Or commit a project-level .mcp.json so your whole team gets it:

{
  "mcpServers": {
    "selvedge": { "command": "selvedge-server" }
  }
}

Docs: https://code.claude.com/docs/en/mcp

.cursor/mcp.json (project) or ~/.cursor/mcp.json (global):

{
  "mcpServers": {
    "selvedge": { "command": "selvedge-server" }
  }
}

Cursor's newer schema also accepts an explicit "type": "stdio"; the command-only form works too (Cursor infers stdio from command). Docs: https://cursor.com/docs/mcp

~/.codeium/windsurf/mcp_config.json:

{
  "mcpServers": {
    "selvedge": { "command": "selvedge-server" }
  }
}

Windsurf hot-reloads the file — no restart needed. The in-app Plugins → View raw config button opens the exact file Cascade reads. Docs: https://docs.windsurf.com/windsurf/cascade/mcp

~/.codex/config.toml:

[mcp_servers.selvedge]
command = "selvedge-server"

Or run codex mcp add selvedge -- selvedge-server. Docs: https://developers.openai.com/codex/config-reference

~/.gemini/settings.json (or .gemini/settings.json per project):

{
  "mcpServers": {
    "selvedge": { "command": "selvedge-server" }
  }
}

Or run gemini mcp add -s user selvedge selvedge-server. Docs: https://github.com/google-gemini/gemini-cli/blob/main/docs/tools/mcp-server.md

Most clients share the same JSON shape — point yours at:

{
  "mcpServers": {
    "selvedge": { "command": "selvedge-server" }
  }
}

If selvedge-server isn't found, use its absolute path (which selvedge-server).

How it works

Selvedge runs as an MCP server. AI agents in tools like Claude Code call Selvedge's tools as they work — logging structured change events to a local SQLite database.

Each event records:

• What changed (entity path, change type, diff)

• When (timestamp)

• Who (agent, session ID)

• Why (reasoning — captured from the agent's context in the moment)

• Where (git commit, project)

The diff is git's job. The why is Selvedge's.

Selvedge tracks its own history

This repo dogfoods Selvedge: its .selvedge/selvedge.db is committed, so a fresh clone ships with Selvedge's own why-history. Clone it and ask why any part of Selvedge changed:

git clone https://github.com/masondelan/selvedge
cd selvedge
selvedge status                       # recent changes to Selvedge itself
selvedge search "telemetry"           # why the opt-in heartbeat shipped
selvedge blame selvedge/semantic.py   # why semantic search was added

Every event was logged by the agents that built Selvedge — the same log_change calls this README asks you to make in your own project.

Entity path conventions

users.email           DB column (table.column)
users                 DB table
src/auth.py::login    Function in a file (path::symbol)
src/auth.py           File
api/v1/users          API route
deps/stripe           Dependency
env/STRIPE_SECRET_KEY Environment variable

Prefix queries work everywhere: users returns users, users.email, users.created_at, and any other entity under the users. namespace.

MCP tools

When connected as an MCP server, Selvedge exposes:

CLI reference

selvedge init [--path PATH]               Initialize in project
selvedge status                           Recent activity summary
selvedge diff ENTITY [--limit N]          Change history for entity
selvedge blame ENTITY                     Most recent change + context
selvedge history [--since SINCE]          Browse all history
              [--entity ENTITY]
              [--project PROJECT]
              [--changeset CS]
              [--summarize]
              [--limit N]
selvedge changeset [CHANGESET_ID]         Show events in a changeset
                  [--list]                or list all changesets
                  [--project NAME]
                  [--since SINCE]
selvedge search QUERY [--limit N]         Full-text search
selvedge prior-attempts ENTITY            Prior attempts + inferred outcome,
                       [--description T]   with the tried → reverted →
                       [--all]             re-opened trail + status line
                       [--window 7d]       (--all widens recall)
                       [--fuzzy TEXT]      add semantic matches (needs the
                                           semantic extra; substring fallback)
selvedge supersede ENTITY                 Re-open a reverted decision —
                  --reasoning TEXT         append-only, links the prior
                  [--constraint TEXT]      reverted event (or --supersedes ID)
                  [--stale-when TEXT]
                  [--supersedes ID]
selvedge index [--model NAME]             Build/update the optional semantic
              [--json]                     embeddings index (selvedge[semantic])
selvedge stale [--entity ENTITY]          Decisions due for a revisit: past
              [--project NAME]            revisit_after + still in use, or
              [--agent NAME]              stale_when matched by a later change
              [--json]                    ("review suggested")
selvedge stats [--since SINCE]            Tool call coverage report (per-tool, per-agent)
selvedge doctor [--json]                  Health check: DB path, schema, hook, MCP wiring
selvedge install-hook [--path PATH]       Install git post-commit hook
                     [--window MIN]       (default 60 minutes)
selvedge backfill-commit --hash HASH      Backfill git_commit on recent events
                        [--window MIN]    (default 60 minutes)
selvedge import PATH                      Import migrations (SQL / Alembic) or
              [--format auto|sql|         an Agent Trace file (agent-trace)
                 alembic|agent-trace]
              [--from-git]                or walk git history for reverts:
              [--since REF|DATE]          revert-message commits + deletions
              [--project NAME]            become change_type="revert" events
              [--dry-run]                 (idempotent on commit + entity)
selvedge export [--format json|csv|       Export history (agent-trace =
                 agent-trace]              Agent Trace v0.1.0 records)
              [--since SINCE]
              [--entity ENTITY]
              [--ndjson]                  agent-trace: one record per line
              [--collapse-by-session]     agent-trace: merge a session into one
              [--output FILE]
selvedge log ENTITY CHANGE_TYPE           Manually log a change
             [--diff TEXT]                CHANGE_TYPE: add, remove, modify,
             [--reasoning TEXT]           rename, retype, create, delete,
             [--agent NAME]               index_add, index_remove, migrate,
             [--commit HASH]              revert, supersede
             [--project NAME]
             [--changeset CS]
             [--revisit-after WHEN]       ISO date or offset (e.g. 90d)
             [--rename-from OLD]          OLD path when CHANGE_TYPE is 'rename'
             [--constraint TEXT]          the principle behind the decision
             [--stale-when TEXT]          what would invalidate it
             [--supersedes ID]            with CHANGE_TYPE 'supersede'
selvedge migrate-paths                    Re-canonicalize stored entity paths
                      [--apply]           (dry-run by default; --apply writes)
                      [--json]

All read commands support --json for machine-readable output.

Relative time in --since:

• 15m → last 15 minutes (m = minutes)

• 24h → last 24 hours

• 7d → last 7 days

• 5mo → last 5 months (mo or mon = months)

• 1y → last year

Unparseable inputs (e.g. --since yesterday) exit with a clear error rather than silently returning empty results. ISO 8601 timestamps are also accepted and normalized to UTC.

Configuration

Coverage checking

Wondering how often your agent actually calls log_change? Two ways to check:

# Quick summary in the terminal
selvedge stats

# Cross-reference against git commits
python scripts/coverage_check.py --since 30d

The coverage script compares your git log against Selvedge events and shows which commits have associated change events. Low coverage usually means the system prompt needs strengthening — see docs/fallbacks.md for guidance.

In CI (GitHub Action)

The same check ships as the Selvedge Coverage Check composite Action, so you can track agent coverage on every push — and optionally fail the build when it drops:

# .github/workflows/selvedge-coverage.yml
name: Selvedge coverage
on: [push, pull_request]
jobs:
  coverage:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0            # full history so commits can be matched
      - uses: masondelan/selvedge@v0.3.9   # pin to a release tag (or @main for latest)
        with:
          since: 30d
          fail-under: "0.5"         # optional: fail below 50% coverage; omit to report only

It writes a coverage summary to the job summary and exposes coverage-ratio, covered, and total as step outputs. The action cross-references your git history against the Selvedge event log, so the runner needs the project's .selvedge/selvedge.db (commit it, or restore it before this step) and full git history (fetch-depth: 0). Inputs: since, window, limit, fail-under, selvedge-version, python-version, working-directory, db-path.

Contributing

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

See CLAUDE.md for architecture details and the phase roadmap.

License

MIT — see LICENSE.