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

Annotations are minimal (readOnlyHint false, destructive false); the description adds useful behavior: public entry, sticker returned, no human decision, completion condition. It doesn't discuss idempotency or repeated signings, but given a simple write tool this is adequate context.

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-load the action and key implications. Every sentence adds information: cost, publicity, completion, no human approval. No wasted words.

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 an output schema present and 100% schema coverage, the description covers the behavioral context an agent needs. It could note that the entry is permanent or that identity fields are optional, but the schema already documents those.

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%, with each parameter documented including verified identity and signature semantics. The description doesn't repeat parameter details but also adds little beyond the schema. Baseline 3 is appropriate because the schema already carries the 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?

Description clearly states the action (signing), the resource (guestbook), and key consequences (free, public, sticker, completion condition). It distinguishes itself from sibling purchase tools by positioning the action as a store errand, not a purchase.

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?

The description gives clear context: free, no human decision needed, open to the visiting agent. It implies this is for routine signings vs other pay-to-do siblings, though it doesn't explicitly name an alternative or exclusion condition.

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