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PostgreSQL MCP Server

PostgreSQL MCP server - query, schema introspection, explain, and health checks for AI assistants

Connector by YawLabs · GitHub account verified by the MCP Registry

IndexedMITLocal (stdio)★ 10
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Works with Claude Code, Codex, VS Code, Cursor, Windsurf, Claude Desktop. Read the repository before you give any tool access to your data.

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About

PostgreSQL MCP server - query, schema introspection, explain, and health checks for AI assistants

Use cases: database-access, monitoring-observability

Reviews

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What this server can do and what it asks for, from its tool list, install config and code. Checked Oct 25, 2026.

Tools
20 read · 0 write · 3 delete
Secrets
None asked for
Install scripts
None found
Runs as
Node.js package

Tools by what they do 23

Read from the source code; the running server may list different tools.

Read 20 · Look things up without changing anything.

  • pg_advisor
  • pg_describe_table
  • pg_health
  • pg_index_advisor
  • pg_inspect_locks
  • pg_io_stats
  • pg_list_extensions
  • pg_list_functions
  • pg_list_roles
  • pg_list_schemas
  • pg_list_tables
  • pg_list_views
Show 8 more tools
  • pg_readonly
  • pg_replication_status
  • pg_search_columns
  • pg_seq_scan_tables
  • pg_table_bloat
  • pg_table_privileges
  • pg_top_queries
  • pg_unused_indexes

Delete 3 · Delete, drop, revoke or wipe things.

  • pg_explain
  • pg_kill
  • pg_query

Network hosts it talks to 7

  • api.github.com · found in code
  • apt.postgresql.org · found in code
  • biomejs.dev · found in code
  • github.com · found in code
  • oamjs.org · found in code
  • postgresql.org · found in code
  • yaw.sh · found in code

Files it touches

  • Your home directory (~)
  • ~/yaw/homebrew-yaw
  • ~/yaw/scoop-yaw

Tools (23)

Read from the source code; the running server may differ. Descriptions are the server’s own words; hidden characters are shown as [U+…].

  • pg_advisorDatabase advisor (DBA lints)read-only

    Description is built at runtime.

  • pg_describe_tableDescribe tableread-only

    Describe a relation: kind (table / view / materialized_view / partitioned_table / foreign_table), columns (name, type, nullable, default, `generated`, `identity`), primary key, foreign keys (outgoing), `referenced_by` (other tables whose FKs point at this one), `constraints` (CHECK / UNIQUE non-PK / EXCLUDE), indexes, and partition info (`partition_of` parent, `partitions` children). Works on views and materialized views too -- PK/FK/constraint/index lists will simply be empty for a plain view. Use `kind` to disambiguate before assuming you can write to the relation. Generated columns (`genera…

  • pg_explainExplain query plancan change or delete data

    Get the query plan for a SQL statement. By default, this uses plain EXPLAIN (no execution). Set `analyze: true` to run the query with EXPLAIN ANALYZE - for non-SELECT statements, ALLOW_WRITES=1 is required (since ANALYZE actually executes the statement). Writes executed during EXPLAIN ANALYZE are rolled back, so you can inspect a plan for an INSERT/UPDATE/DELETE without persisting the rows -- but only what Postgres rolls back is undone: a sequence the statement advanced (nextval, a serial or identity column) stays advanced, and any side effect of a function the statement called that lands outs…

  • pg_healthDatabase health snapshotread-only

    Description is built at runtime.

  • pg_index_advisorRecommend indexes for a workloadread-only

    Description is built at runtime.

  • pg_inspect_locksInspect blocking locksread-only

    Show current lock contention: which sessions are blocked and who is blocking them. Returns blocked PID, blocking PID, lock types, relation being contested, and the queries involved. Use this first when a tool call hangs or the app feels stuck - it's the fastest way to identify a long-held transaction holding a lock. Row shape: one row per (blocked_pid, blocking_pid) pair. A session waiting on multiple blockers appears on multiple rows -- group/deduplicate by `blocked_pid` if you want a per-blocked-session count. Scope: CLUSTER-WIDE, unlike `pg_health` active_queries, which is filtered to the d…

  • pg_io_statsI/O statistics and in-flight async I/Oread-only

    Description is built at runtime.

  • pg_killCancel or terminate a backendcan change or delete data

    Cancel a running query (SIGINT-equivalent) or terminate a backend connection (SIGTERM-equivalent) by PID. Find the PID via `pg_health` active_queries or `pg_inspect_locks`. Requires ALLOW_WRITES=1 since this changes database session state. The role in DATABASE_URL must have permission - cancelling another user's query needs the `pg_signal_backend` role or superuser. Note: `pg_signal_backend` does NOT cover superuser-owned backends - only a superuser can signal another superuser's session. Cancel is graceful; terminate is forceful. `signaled=true` means postgres SENT the signal, not that the ta…

  • pg_list_extensionsList installed extensionsread-only

    List installed PostgreSQL extensions. Returns name, version, schema, and description. Useful to check for pgvector, postgis, pg_stat_statements, uuid-ossp, etc. before writing queries that rely on them.

  • pg_list_functionsList functions and proceduresread-only

    List functions, procedures, and aggregates in a schema. Returns name, arguments, return type, kind (function/procedure/aggregate/window), and implementation language.

  • pg_list_rolesList rolesread-only

    List database roles (users and groups) with their login/superuser/createdb/createrole attributes and inherited role memberships. Use this to answer 'who has access to this database?' without needing to read `pg_authid` directly.

  • pg_list_schemasList schemasread-only

    List non-system schemas in the database. Excludes `pg_catalog`, `information_schema`, and other `pg_*` internals.

  • pg_list_tablesList tables in a schemaread-only

    List tables (and optionally views) in a schema. Returns name, type (table/view/materialized view/foreign), and estimated row count (from `reltuples`; null = no ANALYZE yet on PG 14+; 0 may mean empty or unanalyzed on PG <= 13). Paginate via `limit`/`offset` on very large schemas.

  • pg_list_viewsList views with definitionsread-only

    List views and materialized views in a schema with their SQL definitions. Use this over `pg_list_tables` with `includeViews: true` when you want the view body, not just names.

  • pg_queryRun SQL querycan change or delete data

    Run a SQL query against the configured PostgreSQL database. Postgres itself is the primary safety gate: the role in `DATABASE_URL` enforces what queries can succeed. The recommended posture is a least-privileged role (e.g. one granted `pg_read_all_data`), which makes writes server-rejected regardless of any env var. `ALLOW_WRITES=1` is a secondary belt-and-braces gate - it lifts the in-server `BEGIN READ ONLY` wrapper, but it cannot grant privileges the role lacks. Useful for managed databases where creating a second role is awkward. For read-only access where you want the guarantee in the too…

Show 8 more tools
  • pg_readonlyRun read-only SQLread-only

    Run a SQL statement with no persistent data changes. Always executes inside a `BEGIN READ ONLY` transaction regardless of `ALLOW_WRITES`, so postgres itself rejects any INSERT/UPDATE/DELETE/DDL and the transaction is always rolled back. Use this whenever the goal is to read - SELECT, EXPLAIN, SHOW, VALUES, WITH ... SELECT, etc. Scope caveat for hosts that auto-allow this tool: `READ ONLY` constrains writes to the DATABASE, not every side effect. Functions whose effect is outside the table data - `pg_cancel_backend` / `pg_terminate_backend`, `pg_read_file`, `lo_export`, `COPY ... TO PROGRAM` - …

  • pg_replication_statusReplication statusread-only

    Replication overview: configured replication slots, connected replicas (from `pg_stat_replication`), and current WAL position. Use on primary to spot lagging or disconnected replicas, on replicas to see upstream status. Returns empty arrays on a standalone (non-replicated) database rather than erroring.

  • pg_search_columnsSearch columns by nameread-only

    Search for columns by name across all user schemas. Supports SQL LIKE patterns (`%` matches any substring, `_` matches one character). Case-insensitive. Use this instead of iterating `pg_describe_table` when the user asks 'which tables have X'.

  • pg_seq_scan_tablesFind tables with heavy sequential scansread-only

    Tables with high sequential-scan counts relative to index scans - the first place to look for missing-index candidates. Returns `{rows, stats_reset, stats_reset_age_seconds}`: each row has seq_scans, idx_scans, live tuples, and the ratio. A high ratio on a large table usually means a query is reading the whole table where an index would suffice. Pair with `pg_top_queries` to find which query is doing it. These counters are cumulative since the last statistics reset, so every ratio here is only meaningful relative to the top-level `stats_reset` (and `stats_reset_age_seconds`). A ratio measured …

  • pg_table_bloatEstimate table bloatread-only

    Estimate table bloat (dead tuples + free space) for tables in a schema. Returns live tuples, dead tuples, dead-tuple ratio, last_vacuum / last_autovacuum timestamps, and total relation size. A high dead_ratio with a stale last_autovacuum is a sign a table needs VACUUM. On PostgreSQL 19+ every row also carries `stats_reset`: the last time THAT relation's counters were reset via `pg_stat_reset_single_table_counters()`. Read it before trusting anything else in the row -- a reset zeroes live_tuples and dead_tuples AND clears last_vacuum / last_autovacuum / last_analyze together, so a table reset a…

  • pg_table_privilegesShow table privilegesread-only

    Show which roles have which privileges (SELECT, INSERT, UPDATE, DELETE, TRUNCATE, REFERENCES, TRIGGER) on a table or on every table in a schema. If `table` is omitted, the result spans every table in `schema`, ordered by table then grantee. Use this to answer 'who can write to this table?' or to audit schema-wide access before a migration. Visibility caveat: backed by `information_schema.table_privileges`, which postgres filters by what the calling role can see. A least-privileged role may not see grants involving unrelated third-party roles. For a complete picture, run as a superuser or a mem…

  • pg_top_queriesTop queries by execution timeread-only

    Top N queries by total or mean execution time. Requires the `pg_stat_statements` extension to be installed and enabled (most managed Postgres providers have it on by default). Returns `{rows, stats_reset, stats_reset_age_seconds, dealloc}`: each row has normalized query text (constants replaced with `?`), call count, total/mean/min/max time in ms, rows returned, and cache hit ratio. Use this to find slow queries worth optimizing. `calls` and `total_time_ms` are cumulative since the last `pg_stat_statements_reset()`, so this ranking only describes the window that started at the top-level `stats…

  • pg_unused_indexesFind unused indexesread-only

    Indexes that have never been scanned or have very low usage, largest first. Each unused index costs write amplification (every INSERT/UPDATE maintains it) and disk space, so before adding a new index, check whether the fix is to drop a dead one. Returns `{rows, stats_reset, stats_reset_age_seconds}`. READ THIS BEFORE RECOMMENDING A DROP: `scans` is a counter, not a verdict. It only counts since the last statistics reset, which is why the top-level `stats_reset` and `stats_reset_age_seconds` are part of the answer. If the counters were reset an hour ago, EVERY index looks unused; if `stats_rese…

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    Open issues
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    Last commit
    Oct 15, 2026 (13 days ago)
    Last release
    Oct 11, 2026 (17 days ago)

    From GitHub (fetched Oct 24, 2026).

    Details

    Registry name
    io.github.YawLabs/postgres-mcp
    Version
    0.13.9
    Auth
    No auth
    Packages
    npm @yawlabs/postgres-mcp
    License
    MIT
    Repository
    github.com/YawLabs/postgres-mcp
    Website
    yaw.sh/mcp-servers/postgres-mcp/
    First seen
    Oct 24, 2026
    Last checked
    Oct 24, 2026
    Source
    Official MCP Registrygithub-graphql

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    Cite this page

    PostgreSQL MCP Server. Agent Mart. https://agentmart.dev/connectors/yawlabs-postgres-mcp (last updated 2026-10-24)