key

name	{"[object Object]":null}
description	Query PostgreSQL safely via the {{DISPLAY_NAME}}: read-only SQL, table/schema inspection, multi-environment access, and gated writes/migrations. Triggers on: query the database, run SQL, inspect a table/schema, compare environments, diff data, EF Core migration. Read-only by default; prod is always read-only.

{{DISPLAY_NAME}}

{{TAGLINE}} Tools are exposed as {{TOOL_NAMESPACE}}.

Use this to inspect schema, run read-only SQL, compare environments, and (when explicitly enabled) apply reviewed writes or EF Core migrations. Read-only is the default — reach for write/migration tools only when the user asks and the corresponding flag is on.

Step 0 — Orient

list_environments        // which envs are configured + which are writable
list_tables(environment?) // discover tables
describe_table(table)     // columns, types, keys
get_table_relationships(table)

Read queries (default path)

run_read_query(sql: "SELECT ... WHERE ... LIMIT 100", environment?, limit?, timeoutMs?, explain?)

• Only SELECT and WITH ... SELECT are allowed. Multi-statement and mutation tokens are blocked.
• Always bound results with a LIMIT (server also caps via MCP_DB_DEFAULT_LIMIT/MCP_DB_MAX_LIMIT).
• Use explain:true to see the plan; a warning fires when EXPLAIN cost exceeds PG_EXPLAIN_COST_WARN.
• profile_table, compare_environments, data_diff for profiling and cross-env comparison.

Environment selection

Pass environment explicitly for anything sensitive. PG_DEFAULT_ENVIRONMENT is used when omitted. Only envs in PG_ALLOWED_ENVIRONMENTS are reachable; only those in PG_WRITABLE_ENVIRONMENTS accept writes. prod is force read-only regardless of config.

Writes (OFF unless PG_WRITE_ENABLED=true) — preview → apply → rollback

write_preview(sql, environment)   // returns previewId, approvalToken, affected sample, mandatory-WHERE check
// review the sample + row estimate carefully
write_apply(previewId, approvalToken)
write_rollback(applyId)           // if needed

• A WHERE clause is mandatory for UPDATE/DELETE — unbounded mutations are rejected.
• Approval tokens are HMAC-signed and expire (PG_WRITE_PREVIEW_TTL_MS, default 15 min).

Migrations (OFF unless PG_MIGRATION_ENABLED=true)

migration_status → migration_add / migration_preview → migration_dry_run → migration_apply

Preview and dry-run before applying. Requires the configured .NET project paths.

Guardrails

• Never construct SQL by string-concatenating untrusted input — the server enforces parameterized/whitelisted execution, and you should respect that intent.
• Never echo secrets (connection strings, passwords) back to the user.
• Default to the smallest scope: explicit env, explicit LIMIT, read-only unless asked otherwise.

Configuration (env)

Server entry: node {{ENTRY_PATH}}

A connection source is required — set one of CH_DB_CONNECTION, PG_ENV_*, or CH_APPSETTINGS_ROOTS.

{{ENV_TABLE}}

Tool reference

{{TOOL_LIST}}