x_list_pin_set

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

Annotations already mark this as a non-read-only, idempotent, non-destructive write. The description adds useful behavioral context: it is reversible, reports the resulting `pinned` state, and is disabled when a read-only policy is active. No contradiction with annotations exists.

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 front-load the core purpose, then add behavioral nuance and the read-only policy caveat. Every sentence earns its place, with no redundant restatement of the title or obvious filler.

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?

Given the low parameter count, high schema coverage, and rich annotations, the description is nearly complete for calling the tool. It even covers the result state and policy restriction; it only lacks explicit sibling differentiation, but that is a minor gap.

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 schema already fully documents both `list_id` and `action`. The description mentions `action` semantics but does not add meaning beyond the schema; the `list_id` format is left entirely to the schema, which is acceptable at this coverage level.

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 names the exact verb-resource pair: pin or unpin a list in the authenticated user's list view. It also clarifies the role of `action` and the resulting `pinned` state, making the tool's purpose unmistakable even among many list-related 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?

It clearly states the operation and the context (authenticated user's list view) and explains that `action` selects between pinning and unpinning. However, it does not explicitly name alternative tools or state when not to use it, though the operation is unambiguous enough that an agent can infer it.

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