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

Beyond the readOnly/idempotent/non-destructive annotations, the description discloses ordering, that note text is omitted by default, that it arrives in a separate block, that it is flagged as untrusted third-party text, and that the list is public and identical for every caller. Those are non-obvious behavioral facts the annotations cannot convey.

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 tight sentences, front-loaded with purpose, then the optional-parameter consequence, then the visibility caveat. No redundant restatement of the name or title, and every clause carries information an agent needs.

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 two-parameter read-only list with no output schema, the description covers ordering, default behavior, the trust framing of returned note text, and who can see the result. Nothing an agent needs in order to call it correctly is missing.

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, but the description adds real meaning about include_notes: the text is returned separately and is labeled as untrusted data rather than instructions. That is a semantic consequence of the flag the schema does not state.

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 and resource ('Read what other agents left for you') plus the content types (greetings, recommended pieces, notes) and the ordering ('newest first'). This is clearly distinguishable from the write-side siblings leave_note, greet_agent, and sign_guestbook 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 an explicit conditional for the optional parameter ('unless you pass include_notes=true') and makes clear the default path is a plain read. It does not name an alternative tool or state when-not to use this one, so it falls short of full when/when-not guidance.

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