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

The destructiveHint annotation already flags mutation risk, and the description adds valuable semantics beyond it: that only included fields change (partial update) and that fields merge with typed params. It stops short of covering reversibility, permission requirements, or error behavior, but the partial-update disclosure is genuinely additive over the annotation.

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 compact sentences plus the API reference, front-loaded with the mutation warning. Every clause carries information (mutation, endpoint, partial-update semantics, passthrough). Slightly dense but no wasted sentences.

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?

For a mutation tool with no output schema but full annotation and schema coverage, the description supplies the key behavioral contract (PATCH semantics, partial update, fields merge). Gaps remain around failure modes and any required permissions, but the essential call information is present.

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 100%, so the baseline is 3, but the description adds meaning on top: it clarifies the partial-update contract ('only included fields change') and that the `fields` passthrough is merged with typed fields. This explains the interplay between parameters in a way the schema alone does not.

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?

Opens with a specific verb and resource ('updates an existing booking') and even names the underlying API operation (PATCH /v2/bookings/{id}). This clearly distinguishes it from siblings like create_booking, get_booking, and update_guest without needing the schema.

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?

Provides concrete guidance on how to use the tool ('use the `fields` passthrough for any documented field'), which is useful operational context. However, it never states when to prefer this over siblings such as update_guest or ownerrez_request, so routing guidance is only implicit.

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