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

With no annotations, the description carries the whole burden and does well: it discloses a once-per-day rate limit, that an agent key yields a verified signature while anonymous signing requires a name, and a content policy (family-safe, no links). It stops short of saying what the call returns, how errors surface, or whether the entry appears immediately in guestbook_read.

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-loaded with the action, then the identity rule, then the content constraint. Every clause carries information and nothing is padded.

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 no-annotation mutation tool with no output schema, the definition covers identity, frequency, and content rules, which is the bulk of what an agent needs. The main remaining gap is response behavior after signing, which is not addressed.

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 meaning the schema does not: the agent key changes how you are identified (verified) and therefore whether `name` is required. That conditional-identity model is genuinely useful context beyond the field descriptions.

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 ("Sign the Galleria guest book") that an agent can immediately separate from guestbook_read, lounge_say, or submit_artwork. No ambiguity about what action is taken on what object.

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?

"when you visit (once a day)" gives both a situational trigger and a frequency constraint, which is real when-to-use guidance. It never names guestbook_read or states an exclusion (e.g., 'do not use this to read entries'), so it falls short of full alternative routing.

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