mongo_create_index

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

Without annotations, the description only reveals that the tool performs a write operation and is blocked in readOnly mode. It does not disclose other behavioral traits like idempotency, failure modes, or permission requirements.

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 sentences, front-loaded with purpose and constraint, no unnecessary words. Efficient and to the point.

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?

The description is adequate for a simple creation tool but missing details on return values, error handling, and impact of optional parameters like unique and database. With no output schema, more context would be beneficial.

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 extra meaning beyond the parameter descriptions already present. The 'keys' example from the schema is referenced but not elaborated.

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 action (Create) and the resource (index on a MongoDB collection), which distinguishes it from sibling tools like mongo_drop_index and mongo_list_indexes.

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?

No guidance on when to use this tool versus alternatives, nor any exclusions or prerequisites beyond the readOnly note. The description lacks context for selection among many MongoDB and other database tools.

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