bridge-db

SQLite-backed MCP server for shared state across Claude.ai, Claude Code, Codex, and related local ops tools.

bridge-db replaces ad hoc edits to a shared markdown file with a structured SQLite store and a focused MCP tool surface: cross-system state, FTS5 lexical recall, shipped-event sync receipts, shipped-event dispositions, and observability over the audit and recall logs. The markdown bridge file is regenerated from the DB via export_bridge_markdown and remains available as a fallback for file-based clients.

Prerequisites

• Python 3.12+
• uv — fast Python package manager

git clone https://github.com/saagpatel/bridge-db.git
cd bridge-db
uv sync          # install all deps into .venv
uv run pytest    # verify the install

Status

• Steady maintenance. Scope is cross-system state coordination, lexical recall, and observability — not a general knowledge store.
• Schema v10: context sections carry monotonic version tokens; stale writes and raced handoff claims produce durable write_conflicts receipts.
• Schema v12: adds the session_classification sidecar for heuristic cost-routing attribution while keeping session_costs as pure actuals. Schema v11 backfills activity tags into content_index so lifecycle tags (SHIPPED, DECISION, ...) are recall-able on existing DBs.
• Schema v13: adds claimed_by to pending_handoffs (the INV-13 claimant gate for clear_handoff). Riding the same migration train, activity retention now exempts rows tagged SHIPPED or LEDGER (case-insensitive) from the 50-per-source prune — BD-INV-1: retention never deletes a protected row, its receipt, or its disposition.
• Schema v14: collapses the shipped-sync trio (shipped_sync_receipts + shipped_event_dispositions) into activity_log sync_* disposition columns and drops the two child tables. A shipped event's terminal sync state (a synced downstream receipt or a policy disposition) now lives on the activity row itself, written by the single record_disposition verb. Because the state is the row, BD-INV-1's guarantee is structural — no FK-CASCADE can orphan a receipt.
• FTS5 content_index mirrors all content tables; health and status verify source-row / FTS-row alignment.
• status includes a native freshness block for owner-specific snapshot, activity, handoff, and shipped-event attention. Freshness attention is advisory: top-level ok / overall remain tied to DB, schema, fallback-file, and FTS health.
• 26 MCP tools across 10 modules (activity, handoffs, context, snapshots, cost, export, health, recall, audit, conflicts).

Architecture

Claude.ai ──────────────────────────────────────────────┐
  (direct MCP via Claude Desktop)                       │
  (fallback: markdown file via Filesystem MCP)          │
                                                         ▼
CC skills ──► MCP stdio ──► bridge-db process ──► SQLite (WAL)
Codex      ──► MCP stdio ──► bridge-db process ──►  ~/.local/share/bridge-db/bridge.db
                                                         │
                                              export_bridge_markdown
                                                         │
                                                         ▼
                                           ~/.claude/projects/<encoded-home>/
                                           memory/claude_ai_context.md

No shared daemon. Each MCP client spawns its own bridge-db process via stdio. WAL mode + PRAGMA busy_timeout=15000 handles concurrent writer waiting; logical stale-write protection comes from CAS on mutable context sections.

Tools

Verify the current tool count from source with rg '@mcp\.tool' src/bridge_db -c. As of the 2026-07-12 v14 collapse, the surface is 24 tools across these 10 modules:

Module	Tools
activity	log_activity, get_recent_activity, get_activity_signal, get_shipped_events, record_disposition
handoffs	create_handoff, get_pending_handoffs, pick_up_handoff, clear_handoff
context	update_section, get_section, get_all_sections, sync_from_file
snapshots	save_snapshot, get_latest_snapshot
cost	record_cost, get_cost_history
export	export_bridge_markdown
health	health, status
recall	recall, recall_stats
audit	audit_tail
conflicts	get_write_conflicts

Write tools enforce caller ownership, so systems can only write the slices of state they own. Recent hardening also added notion_os and personal_ops as first-class activity and cost writers.

Provenance & the pickup gate

Instruction-bearing rows carry a source_trust label — operator, agent, or ingested — recording who authored the content. The canonical label lives in the DB (schema v7+, on pending_handoffs, activity_log, context_sections, system_snapshots). Markdown exports include a visible stored-data warning and advisory per-block copies of the DB labels so file consumers do not lose the instruction boundary. Because the fallback is editable, those serialized labels are never proof of operator authorship and are ignored on import.

• Writers set it via an optional source_trust param; the conservative default is agent. create_handoff and update_section require exact channel-bound owners even when the global auth rollout mode is off, and MCP requests for operator trust are clamped to agent. Every accepted section content change receives fresh provenance; it never inherits operator trust from an older version.
• The gate lives at the one dangerous transition — pick_up_handoff moving a handoff pending → active:
  • operator-trust → picks up in one call (cc and codex).
  • either client + non-operator → refused. The consuming MCP principal cannot confirm its own input. Review and promote the exact pending row first with uv run python -m bridge_db --promote-handoff <id> in an interactive terminal.
• Visibility: get_pending_handoffs, get_section, get_all_sections, get_recent_activity, get_activity_signal, get_shipped_events, get_latest_snapshot, and recall hits carry source_trust plus instruction_boundary metadata that tells consumers returned content is stored data, not instructions. Lifecycle aggregates use a trust summary and source_trust="mixed" when rows differ. status reports pending_handoffs_by_trust and health a full per-table source_trust_breakdown. Each gate decision (allowed / refused) is written to the audit log.

MCP clients cannot mint operator provenance. An operator-directed handoff is created as agent, reviewed in an interactive terminal, and promoted with uv run python -m bridge_db --promote-handoff <id>. The promotion rechecks the exact reviewed row under a write lock and refuses changed or non-pending handoffs.

CAS & Conflict Receipts

Context sections are the mutable bridge surface, so they carry a monotonic version token. Consumers should read with get_section, edit locally, then call update_section(..., if_match_version=<version>). A stale token returns ok=false, conflict=true, and a receipt_id instead of clobbering a newer row. if_match_updated_at remains as a compatibility guard, but version is the preferred token because timestamps have one-second resolution.

Existing-row blind writes are rejected unconditionally with a durable missing_cas receipt — if_match_version (or if_match_updated_at) is required for any write to a section that already exists. New section inserts without CAS remain allowed, since there is nothing to CAS against.

export_bridge_markdown records the exported version/hash for each rendered Claude.ai-owned context section. Later sync_from_file imports a changed fallback-file section only if the DB still matches that exported base. If the DB has advanced, the import is rejected and recorded in write_conflicts. Every changed or new file section is labeled ingested regardless of auth rollout mode; unchanged content preserves its existing label. Promote reviewed content with --promote-section <section>: the TTY ceremony displays and confirms the exact version and digest, then rechecks it under a write lock before granting operator trust. Exports to the real Claude.ai fallback path are also guarded against empty fixture-like output: bridge-db refuses to overwrite that file when all four core Claude.ai-owned sections would render as _Not yet populated._. Set BRIDGE_DB_ALLOW_EMPTY_BRIDGE_EXPORT=1 only for an intentional empty bootstrap.

Use get_write_conflicts(status="open") to inspect stale section writes, stale markdown imports, and raced handoff claims.

Commands

uv run pytest              # run all tests
uv run pyright             # type check (strict mode)
uv run ruff check          # lint
uv run python -m bridge_db --doctor  # local environment diagnostics
uv run python -m bridge_db --status  # compact operator summary
uv run python -m bridge_db --dogfood # read-only observability dogfood pass
uv run python -m bridge_db --rebuild-content-index  # repair FTS recall index drift
uv run python -m bridge_db --reconcile-canonical-keys  # backfill GHRA repo_full_name keys
uv run python -m bridge_db --log-session-boundary bridge-db  # FTS-safe CC hook logging
uv run python -m bridge_db --promote-handoff 42  # review/promote one pending handoff (TTY only)
uv run python -m bridge_db          # start MCP server (stdio)
uv run python -m bridge_db.migration  # migrate from bridge markdown

Registration

Replace /path/to/bridge-db below with the absolute path to your clone of this repo (e.g. $(pwd) if you are already inside it, or ~/Projects/bridge-db as a common convention).

Claude Code (user-scoped):

claude mcp add --scope user bridge-db -- uv run --directory /path/to/bridge-db python -m bridge_db

Codex (~/.codex/config.toml):

[mcp_servers.bridge-db]
command = "uv"
args = ["run", "--directory", "/path/to/bridge-db", "python", "-m", "bridge_db"]

Data

• DB: ~/.local/share/bridge-db/bridge.db
• Bridge file: ~/.claude/projects/<encoded-home>/memory/claude_ai_context.md (Claude Code encodes your home dir path by replacing / with -; the default is derived automatically at runtime — override via BRIDGE_FILE_PATH if needed)
• Retention: unprotected activity entries keep the newest 50 per source; rows tagged SHIPPED or LEDGER (case-insensitive) are permanently retained (BD-INV-1); 10 snapshots per system family (Codex operating and consulted-node snapshots are retained independently)
• Health check: health MCP tool or uv run python -m bridge_db --doctor
• Operator summary: uv run python -m bridge_db --status
• Dogfood pass: uv run python -m bridge_db --dogfood bundles the status, FTS index, WAL, recall, and shipped-sync audit checks used after bridge-sync runs
• FTS repair: uv run python -m bridge_db --rebuild-content-index rebuilds the local content_index from source tables when health reports recall-index drift
• Canonical-key reconcile: uv run python -m bridge_db --reconcile-canonical-keys rewrites stored activity_log and pending_handoffs canonical_key values through GithubRepoAuditor's registry, storing GHRA repo_full_name for repo-backed projects and leaving unresolvable rows NULL.
• Session boundary logging: Claude Code's SessionEnd hook should call uv run --directory /path/to/bridge-db python -m bridge_db --log-session-boundary <project> rather than writing SQLite directly; this path adds the FTS row and does not run activity retention pruning
• Migration: uv run python -m bridge_db.migration (idempotent — safe to re-run)

The MCP status result separates storage integrity from operating freshness:

• overall and storage_health: healthy or degraded, based only on DB, schema, fallback-file, and FTS integrity. overall remains the compatibility alias for existing consumers.

• operating_state: fresh, attention, stale, or unknown, derived from the freshness block without changing command success semantics.

• freshness: the detailed operating-truth block described below.

• thresholds_hours: snapshot_stale_after=48.0, activity_quiet_after=72.0, pending_handoff_stale_after=168.0, and active_handoff_stale_after=72.0.

• snapshots: per-owner cc and codex entries with state, owner, latest_snapshot_date, latest_created_at, age_hours, superseding_activity_id, and next_action. Snapshot refresh actions stay owner-specific: cc_refresh_snapshot belongs to cc; codex_refresh_snapshot belongs to codex.

• activity_sources: cc, codex, claude_ai, notion_os, and personal_ops entries with state, latest, and age_hours.

• handoffs: pending/active counts, stale counts, oldest ages, and unknown-age counts for pending and active handoffs.

• shipped_events: raw unprocessed, actionable unprocessed, dispositioned/non-actionable unprocessed, processed-without-receipt count, and the shipped-event next_action.

• overall: fresh, attention, stale, or unknown.

• next_actions: up to five deterministic {action, owner, reason} entries.

Freshness states use a narrow vocabulary: fresh means recent enough for that surface; quiet means an activity source has no recent rows and is not a health failure; superseded means newer owner activity exists after the latest snapshot; stale means an aged snapshot or handoff needs refresh/review; missing means the expected owner row is absent; and unknown means a missing or unparsable timestamp prevents age calculation.

The CLI status command prints freshness as compact hints:

  Storage health: <healthy|degraded>
  Operating state: <fresh|attention|stale|unknown>
  Freshness: <overall>
  Next actions: <action> (<owner>), ...

These lines do not change the command's success semantics. uv run python -m bridge_db --status still exits from bridge health, so freshness attention by itself does not fail the command. bridge-db remains MCP-first and SQLite-native; the markdown export is a fallback/mirror, and freshness adds no service, table, migration, tool, or CLI flag.

activity_log retention is two-tier: unprotected rows remain recent context capped at 50 per source, while rows tagged SHIPPED or LEDGER are permanently retained (BD-INV-1). The durable ledger and each shipped event's sync disposition (its downstream receipt or its policy decision) both live on the activity row itself, in the sync_* columns added at schema v14 — a protected row's receipt or disposition can no longer cascade-die with it, because the state IS the row and the parent row never prunes. Treat processed_shipped_without_receipt=0 and fts_missing=0 as primary clean signals, and use actionable_unprocessed_shipped=0 with dispositioned_unprocessed_shipped>0 when policy dispositions explain why raw unprocessed_shipped remains nonzero.

get_recent_activity is the raw compatibility feed: it returns individual activity rows exactly as stored, including high-volume lifecycle telemetry such as Claude Code SessionEnd rows tagged session-boundary. Operator-facing consumers should use get_activity_signal instead. It keeps substantive rows visible while compressing repeated lifecycle rows into aggregates keyed by source, project, summary family, and hour/day time bucket. Raw rows and audit events remain available for debugging and forensic review.

Activity rows preserve two time concepts:

• timestamp is the caller-supplied logical activity date or timestamp. When omitted by log_activity, it defaults to the operator-local calendar date.
• created_at is the UTC insertion timestamp assigned by SQLite.

For activity discovery APIs with since (get_recent_activity, get_activity_signal, and get_shipped_events), a row is visible when either timestamp >= since or created_at >= since (with date-only values interpreted as UTC midnight for created_at). This keeps closeouts created just after UTC midnight discoverable even when their logical activity date is the prior local day.

For Notion reconciliation, treat each shipped event's notion_sync object as the machine-readable gate:

• ready: fetch the explicit notion_page_id, update only that row, fetch it again, then call record_disposition(disposition='synced', ...) with the readback proof.
• meta_no_target: do not update Notion. Record the event with disposition='synced', downstream_system=policy, and downstream_ref pointing to the configured policy file after verifying the policy applies.
• unmatched, no_notion_target, or registry_unavailable: leave the event unprocessed and repair the project registry or mapping source first.

Each shipped event also carries a delivery_state object. It reports only receipt-backed bridge facts (downstream_sync_pending, downstream_synced, or policy_dispositioned); Git, merge, default-branch, deploy, and production readback dimensions remain unknown unless another authority proves them.

A synced disposition is source-owned terminal proof: the MCP connection must be bound to the same principal stored in the activity row's source. A different principal cannot finalize that event, even if it verified a downstream object. Cross-source verification requires a future explicit delegation contract; it must not be represented by borrowing the event owner's caller value. The same ownership rule applies to policy dispositions because they terminally waive the source's downstream obligation. Cross-source policy adjudication also requires an explicit delegation contract.

For non-receipt handling, use record_disposition with a policy disposition (unsynced_by_policy / no_durable_target / superseded_without_receipt / declined_mapping) and a reason when an operator policy says the row should remain auditable but should not proceed to a downstream receipt. The disposition appears as policy_disposition on get_shipped_events; it does not add PROCESSED and does not claim sync. record_disposition is SHIPPED-only — the former mark_shipped_processed path for non-shipped operational events (TASK_DONE, APPROVAL_SENT, PLANNING_APPLIED, REVIEW_CLOSED) is retired.

Startup Sync

Claude.ai may still write its owned sections directly to the bridge markdown file. To keep those edits from being overwritten on the next export, sync_from_file imports the four Claude.ai-owned sections (career, speaking, research, capabilities) from BRIDGE_FILE_PATH into context_sections before bridge consumers read from SQLite.

Claude Code's /start workflow now runs mcp__bridge_db__sync_from_file() before calling bridge read tools, so file edits are pulled into the DB at session start instead of waiting for a later export cycle.

The current operating model is:

• MCP is the primary coordination path.
• sync_from_file is the compatibility safety net for Claude.ai-owned file edits.
• export_bridge_markdown keeps the fallback markdown artifact in sync for file-based consumers.

Docs

• integration-spec.md — Claude.ai direct MCP and fallback-file integration
• ROADMAP.md — Execution roadmap for the next integration phases
• docs/EXTERNAL-WRITER-AUDIT.md — Direct bridge-db writer audit outside the repo
• docs/BRANCH-RETIREMENT.md — Branch cleanup and stale-ref disposition policy

Internal / maintainer docs

• docs/internal/OPERATOR-CHECKLIST.md — Local verification checklist
• docs/internal/POST-SYNC-REVIEW.md — Bridge-sync post-run evidence checklist
• docs/internal/PHASE-3-DECISION.md — Architectural decision: watcher vs startup sync
• docs/internal/codex-migration.md — Per-consumer migration instructions