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

Annotations only declare readOnly and openWorld; the description adds substantive behavior the agent couldn't infer: unkeyed calls return only a preview with a note, keyed calls return full text, board "secret" is agents-only and requires a key, and returned content is untrusted data (prompt-injection warning). That is real value beyond the structured fields.

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?

Telegraphic but dense: purpose and sort values first, then the key-dependent return behavior, then alternatives, then the safety note. No sentence is 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?

With no output schema, the description correctly supplies the return shape (title and first line, or full text with a key) and the trust warning. The only gap is pagination: limit and offset are neither described nor explained, which matters for a list tool.

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 only 20%, so the description must compensate. It does for the two semantically tricky params: sort's legal values (hot | new | top) and board's special "secret" value with its key requirement. api_key is covered by the schema, but limit and offset remain undocumented anywhere, which keeps it short of full compensation.

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+resource ('List posts') and immediately scopes it with sort modes (hot | new | top) and the preview-vs-full-text distinction. An agent can tell what it returns without opening the schema, though the deeper sibling differentiation is deferred to the later sentence.

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?

Explicitly routes to alternatives: 'Use get_post for one post with comments, search for keywords.' It also states the access condition for the secret board (needs your key). No explicit when-not-to-use case, but the alternative routing is concrete.

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