MongoDB exploration with agent-mongo

agent-mongo is a read-only CLI binary on $PATH. All output is JSON to stdout. Errors go to stderr as { "error": "..." } with non-zero exit.

Quick start (connections)

Set up a connection:

agent-mongo connection add local "mongodb://localhost:27017/myapp" --default
agent-mongo connection test

For authenticated connections, store credentials separately:

agent-mongo credential add acme --username deploy --password secret
agent-mongo connection add prod "mongodb+srv://cluster.example.net/myapp" --credential acme --default

Exploring a database

agent-mongo database list                                # all databases with sizes
agent-mongo collection list myapp                        # all collections in myapp
agent-mongo collection schema myapp users                # infer schema from samples
agent-mongo collection schema myapp users --depth 2      # limit nesting depth
agent-mongo collection schema myapp events --limit 50    # paginate large schemas
agent-mongo collection schema myapp events --limit 50 --skip 50  # next page
agent-mongo collection indexes myapp users               # index key patterns
agent-mongo collection stats myapp orders                # document count, sizes
agent-mongo database stats myapp                         # database-level statistics

Querying documents

agent-mongo query find myapp users --filter '{"age":{"$gte":21}}' --limit 10
agent-mongo query find myapp orders --sort '{"createdAt":-1}' --projection '{"status":1,"total":1}'
agent-mongo query get myapp users 665a1b2c3d4e5f6a7b8c9d0e      # by _id (auto-detects ObjectId)
agent-mongo query get myapp users 665a1b2c3d4e5f6a7b8c9d0e --projection '{"name":1,"email":1}'
agent-mongo query count myapp orders --filter '{"status":"pending"}'
agent-mongo query sample myapp users --size 10                    # random documents
agent-mongo query sample myapp users --size 10 --filter '{"status":"active"}'  # filtered sample
agent-mongo query distinct myapp orders status                    # unique values

All JSON arguments (--filter, --sort, --projection, --pipeline) accept MongoDB Extended JSON for BSON types:

agent-mongo query find myapp events --filter '{"createdAt":{"$gt":{"$date":"2026-01-01T00:00:00Z"}}}'
agent-mongo query find myapp users --filter '{"_id":{"$oid":"665a1b2c3d4e5f6a7b8c9d0e"}}'

For large result sets, use --stream for NDJSON output (one JSON object per line), which bypasses query.maxDocuments:

agent-mongo query find myapp events --filter '{"type":"click"}' --stream
agent-mongo query aggregate myapp orders '[{"$group":{"_id":"$status","count":{"$sum":1}}}]' --stream

Aggregation

agent-mongo query aggregate myapp orders '[{"$group":{"_id":"$status","count":{"$sum":1}}}]'
agent-mongo query aggregate myapp orders --pipeline '[{"$group":{"_id":"$status","count":{"$sum":1}}}]'
agent-mongo query aggregate myapp events '[{"$match":{"type":"purchase"}},{"$group":{"_id":"$userId","total":{"$sum":"$amount"}}}]'

Pipeline can be passed as a positional argument, via --pipeline flag, or piped via stdin.

Write stages ($out, $merge) are rejected — the CLI is strictly read-only.

Connection management

agent-mongo connection list                              # saved connections + defaults
agent-mongo connection add staging "mongodb://..." --credential acme
agent-mongo connection update prod --credential new-cred
agent-mongo connection set-default staging
agent-mongo connection remove old-conn
agent-mongo connection test prod                         # verify connectivity (positional alias)
agent-mongo connection test -c prod                      # also works with -c flag

Connection resolution: -c flag > AGENT_MONGO_CONNECTION env > config default > error listing available connections.

Credential management

agent-mongo credential add acme --username deploy --password secret
agent-mongo credential list                              # passwords always redacted
agent-mongo credential remove acme --force               # even if connections reference it

Credentials are stored separately from connections. When you rotate a password, just re-add the credential — all connections referencing it pick up the new auth automatically.

LLM-safe entry with --form

When you (the agent) are driving the CLI on a user's local machine, do not put a real password on the command line — you'll see it in your own argv. Use --form to escalate the secret to a native OS dialog instead. The user types into the OS popup; the secret never enters the agent's context.

agent-mongo credential add acme --form                              # both fields prompted
agent-mongo credential add acme --username deploy --form            # only password prompted

Failure modes return a structured error with fixableBy:

• human — no GUI session available (SSH, headless host). Ask the user to run on their local machine, or fall back to non-interactive --username <u> --password <secret>.
• retry — user cancelled the dialog. Re-running the same command is the right next step.

Truncation

Any string field exceeding truncation.maxLength (default 200) gets truncated with … and a companion {field}Length key showing original length.

agent-mongo --full query find myapp posts                # expand all fields
agent-mongo --expand description query find myapp posts  # expand specific field

These are global flags — place them before or after the command.

Timeout

Default timeout is 30s (configurable via query.timeout). Applies to both connection and query phases. Override per-command:

agent-mongo --timeout 60000 query find myapp large_collection --filter '{"status":"active"}'
agent-mongo --timeout 120000 collection schema myapp events

Configuration

agent-mongo config list-keys                             # all keys with defaults/ranges
agent-mongo config set defaults.limit 50
agent-mongo config get query.timeout
agent-mongo config reset                                 # restore defaults

Key settings: defaults.limit (20), defaults.sampleSize (5), defaults.schemaSampleSize (100), query.timeout (30000ms), query.maxDocuments (100), truncation.maxLength (200).

Safety

• Read-only: No write operations exist
• Aggregation: $out and $merge stages rejected
• Result cap: query.maxDocuments (default 100) — use --stream to bypass
• Timeout: applies to both connections and queries (default 30s), override per-command with --timeout <ms>

Per-command usage docs

Every command group has a usage subcommand with detailed, LLM-optimized docs:

agent-mongo usage                  # top-level overview
agent-mongo connection usage       # connection + credential commands
agent-mongo credential usage       # credential management
agent-mongo database usage          # database commands
agent-mongo collection usage       # collection commands
agent-mongo query usage            # all query commands
agent-mongo config usage           # settings keys, defaults, validation

Use agent-mongo <command> usage when you need deep detail on a specific domain before acting.

References

• references/commands.md: full command map + all flags
• references/output.md: JSON output shapes + field details