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

Annotations mark destructiveHint=true, and the description adds valuable behavioral context: it is a WRITE operation, uses PATCH semantics, and only the provided fields are changed. This prevents the assumption that the request performs a full replacement.

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?

Three short sentences, each earning its place: the WRITE flag, the core purpose, the partial-update behavior, and the endpoint. No filler or redundancy, and the most important constraint is front-loaded.

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 an update tool with 100% schema coverage and destructiveHint annotation, the description covers the essential operation, partial-update behavior, and endpoint. It does not describe response format, but no output schema is provided and the description is otherwise sufficient for 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 100%, so parameters are already documented. The description adds the key semantic that only provided fields are changed, which clarifies how optional parameters behave during an update—beyond what the individual field descriptions offer.

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 uses a specific verb ('Update') and resource ('an existing video'), clearly distinguishing this from sibling create/delete/get/list tools. The endpoint PATCH /videos/{videoId} reinforces the operation without ambiguity.

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 phrase 'existing video' clearly indicates this tool is for modifying already-created videos, which excludes creation, deletion, or retrieval. It lacks explicit alternatives or when-not-to-use statements, but the context is unambiguous among the sibling tools.

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