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

The description adds meaningful behavior beyond annotations: partial update semantics ('at least one field is required') and the specific 409 DUPLICATE_NAME collision failure. Annotations already signal read/write/destructive/idempotent traits, and the description supplements them without contradiction.

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 concise sentences front-load the core operation and error behavior. Every clause adds usable information with no repetition of schema descriptions.

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 3-parameter update tool, the description covers use case, partial-update constraint, and error condition; annotations cover safety properties. Success return value is not described, but that isn't essential for an agent deciding whether to call it.

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; the description adds value by clarifying the at-least-one-field requirement that the schema itself doesn't express (schema only requires setId). It also ties 'name and/or channels' to the update intent.

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'), names the resource ('channel set'), and specifies the mutable fields ('name and/or channels'). It also states the partial-update semantics, which distinguishes it from create/delete channel set operations among siblings.

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 explicitly says 'Use this when the user wants to rename a channel set or change its channels,' giving clear invocation context. It doesn't name the create/delete alternatives or state when not to use this tool, but the use-case phrasing is specific enough.

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