List the connection profiles from the anydb config file (~/.anydb/db.json): name, description, driver, which one is the default, and whether it is read-only. Call this first whenever you do not already know a profile name, then pass the name to the other tools as "profile". The result never contains a connection string, a host, a username or a password -- not masked, absent -- because this text goes into your context window and a config file is writable by anyone who can write files. If there is no config file, use "uri" with the other tools instead.

Run one statement against one database (PostgreSQL, MySQL/MariaDB, SQLite, MongoDB or Redis, inferred from the connection). READ-ONLY BY DEFAULT: writes are refused unless "readOnly" is false, and statements that change schema or privileges additionally require "allowDestructive" to be true. Call db_list and db_schema first so table and column names are not guessed, and prefer "params" over inlining values in "query" so the values never appear in the statement text. Put a LIMIT in every query: results are capped anyway, and a cap you did not ask for is how a table gets silently half-read. MongoDB: "collection" is required and "action" picks the operation -- find, count, distinct, aggregate and explain read; insert, update, updateOne, replace, delete and deleteOne write and need "readOnly": false. Prefer the *One actions: one document, not every match. Redis: "query" is a single command such as GET or SCAN.

Describe the structure of a database: tables and their columns for SQL, collections with their indexes for MongoDB, keyspace statistics for Redis. Call it before writing a query so names are not guessed -- it is almost always cheaper than a failed query. Runs read-only introspection statements only, never a statement of yours, and "table"/"collection" are bound as parameters wherever the driver allows rather than pasted into SQL. "detail": "full" adds foreign keys, index definitions, primary and unique constraints, row estimates, and inferred field schemas for MongoDB.

Return the execution plan for a statement WITHOUT running it. Read-only by construction: the statement is planned and not executed, so this is the safe way to catch a sequential scan over a large table and the cheapest way to find a missing index. ANALYZE variants are refused here on purpose, because "EXPLAIN ANALYZE" runs the statement it plans. MongoDB: pass "collection" and a find filter as "query"; a pipeline cannot be explained, use db_query action "aggregate" with a small limit. Redis has no plans, so this tool refuses it.

Ask the database about itself: reachable or not, server version, the role this server authenticated as, whether that role or the server is read-only, object counts, and this server's pool and cache state. Use it instead of guessing at why a connection or a write failed. Note what "readOnly": false does and does not do: it is a request to THIS server, not a security boundary. The boundary is the database role -- a role holding INSERT will succeed whatever these flags say, and a role without them will fail however many are set.