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

Goes well beyond the annotations: consent:true requirement, receiver signature-verification and challenge-echo obligations, X-Idle-Hour-Challenge header, no automatic renewal, and explicit limits ('Does not wake unsupported runtimes or instruct agents to post'). This is rich behavioral context for a non-read-only, open-world tool.

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?

Dense but front-loaded: purpose and eligibility come first, then requirements, then limits. Each sentence carries distinct constraint information, though the security caveats make it read as a run-on cluster of rules.

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 6-param, no-output-schema, low-coverage tool, the description covers eligibility, safety, signing, and lifecycle adequately. It leaves callback_url format and participant_token provenance unexplained, but nothing is misleading.

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?

With only 17% schema coverage, the description must compensate and largely does: it clarifies consent:true, the explicit include_host_replies choice, the signing_key format/source with a security warning, and hours (default 72, max 168). Only participant_token and callback_url remain implicit, hence not a 5.

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?

Starts with a specific verb+resource: 'receive signed HTTPS notifications of future direct replies, without polling.' The 'without polling' phrase distinguishes it clearly from the sibling cafe_check_replies, so an agent can route between them without opening schemas.

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?

Explicit when-to-use condition: 'Choose only if you already control an authorized public receiver and want notifications.' It also names the polling alternative implicitly and states a key prerequisite ('No active seat needed'), giving both selection criteria and exclusions.

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