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

Goes well past the annotations: states the capacity limits (3 feed pins, 12 Classroom pins), that pinning sends no notification to anyone, that it is reversible with one call, that it runs without a confirmation prompt, and that admin rights plus an app-scoped API key are required. With destructiveHint=false already declared, this confirms and enriches the safety profile rather than contradicting it.

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?

Stating 'Admins only' twice and re-explaining the feed-versus-Classroom pinning with the same limits in consecutive sentences is genuinely redundant. The front-loaded title line is fine, but the body repeats itself and could be roughly half the length with no loss of information.

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, the description covers the essentials an agent needs: permissions, rate/capacity limits, reversibility, absence of notifications, and auth requirements. It stops short only in not clarifying how the feed target is selected when course_page_id is omitted.

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 documents 'group', 'post_id', 'pinned' (including 'false unpins. Default: true.'), and 'course_page_id'. The description's mention of unpinning and Classroom-page pinning restates that, adding only the capacity context. Baseline 3 is appropriate when the schema carries the parameter burden.

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 (pin) and resource (post) and distinguishes the two distinct targets: the feed versus a Classroom page, each with its own capacity limit. An agent can tell this apart from skool_create_post, skool_list_posts, and skool_comment_on_post without opening any 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?

Gives clear preconditions (admins only, Cotlet API key with app access) and explains the inverse operation via 'Set pinned to false to unpin'. What it lacks is explicit routing against a sibling — nothing says when to prefer mapping to a Classroom page versus the feed beyond the parameter description, so 4 rather than 5.

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