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

Annotations already declare idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds genuine behavioral context the annotations do not: partial-update semantics (untouched fields are preserved) and the fact that 'type' cannot be modified after creation.

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 compact clauses, front-loaded with the operation and its semantics before the cross-reference and endpoint mirror. No filler or redundancy.

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 14-parameter nested mutation tool with rich schema coverage and no output schema, the description covers operation semantics and field scope adequately. It stops short of permissions, error behavior, or constraints around editing a live stream, though some of those live in the schema (e.g. preserve_state).

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 100%, so the 14 parameters are fully documented and the baseline is 3. The description adds cross-tool meaning the schema cannot convey by mapping the accepted field set to create_stream minus the creation-only 'type', which helps an agent reason about what it may send.

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 (partially update) and resource (a stream), with PATCH semantics spelled out as 'only provided fields change'. It also explicitly distinguishes itself from create_stream by noting the shared field set minus the creation-only 'type' field, and anchors the operation to the underlying REST endpoint.

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?

Usage is implied rather than stated: the create_stream cross-reference tells the agent this is the edit path for an existing stream, but there is no explicit when-to-use versus get_stream/delete_stream/update_media, and no prerequisites or conditions (e.g. live-stream state) are called out.

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