mongo_update_one

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries full burden. It only discloses the readOnly blocking behavior. It fails to mention important behaviors: only the first matched document is updated, no update if no match (unless upsert), and no details on side effects or error conditions.

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?

The description is very concise with only two sentences, no unnecessary words. It could be more structured (e.g., bullet points), but it effectively communicates the core purpose and a key constraint.

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?

Despite having 6 parameters, no output schema, and no annotations, the description omits critical context: return value, behavior with multiple matches, mutation implications, and required permissions. It is incomplete for safe and correct invocation.

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 coverage is 50%, and the description adds no additional parameter semantics beyond what the schema already provides (e.g., 'JSON string'). It does not explain filter syntax, update operators, or the effect of the upsert parameter.

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?

The description clearly states the tool's action: 'Update a single document matching filter in MongoDB'. It distinguishes from siblings like mongo_update_many by specifying 'single document', and notes a blocking condition when readOnly mode is enabled.

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 only mentions blocking in readOnly mode, but provides no guidance on when to use this tool versus alternatives like mongo_update_many or mongo_insert_one. It lacks context on appropriate use cases or prerequisites.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.