Insert, update, or delete MongoDB documents on writable connections, enabling agents to modify data while blocking writes to read-only connections.
Write to MongoDB (action: insert|update|delete). Only allowed on writable connections (read_only=false).
| Name | Required | Description | Default |
|---|---|---|---|
| action | Yes | ||
| payload | Yes | ||
| database | No | ||
| collection | Yes | ||
| connection_id | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden, and it does disclose the key permission gate (writable connections only). What it omits is significant for a mutation tool: that delete is destructive, whether update requires a filter, whether upserts are possible, and what a success/failure response looks like.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two short sentences, front-loaded with the verb and resource, with the constraint immediately after. Zero filler; the only shortfall is that the brevity comes at the cost of information the agent actually needs.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
This is a mutation tool with no annotations, no output schema, a nested free-form `payload`, and 0% parameter documentation. Given that complexity, the description is under-specified: an agent cannot tell from it what shape `payload` must take per action or what happens to matched records on delete.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0% across 5 parameters, so the description must compensate and mostly doesn't. It adds the allowed values for `action` (which the schema does not enumerate) but says nothing about the critical ambiguity of `payload` — a document for insert versus a filter for update/delete — nor about `database`, `collection`, or `connection_id`.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource ("Write to MongoDB") and enumerates the three operations (insert|update|delete), which lets an agent separate it from the read-side siblings mongo_find and mongo_aggregate. It stops short of distinguishing the semantics of the three actions, but the core purpose is unambiguous.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives one hard prerequisite — the connection must be writable (read_only=false) — which is genuinely useful usage guidance. However, it never explicitly says when to pick this over mongo_find or db_execute, or how to choose between insert/update/delete; routing is only implied by the verb "write".
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.