aamio_pending

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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false. The description adds valuable context beyond annotations: it explains the semantics of 'unknown' (not undelivered) and warns against duplicate sends. It doesn't contradict annotations. Minor gap: no detail on how results are returned, but no output schema exists.

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 sentences, each earning its place: definition of scope, clarification of 'unknown', and actionable guidance. Front-loaded with the core purpose.

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 zero-parameter read-only tool, the description is nearly complete. It explains the purpose, the meaning of the key term, and the behavioral implication. It doesn't describe the output format, but with no output schema and a simple list concept, this is a minor gap.

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?

The tool has zero parameters, so the schema provides no parameter semantics. The description compensates by explaining what the tool returns (pending messages) and the meaning of 'unknown'. Baseline 4 for zero params is appropriate; the description adds context about the result set.

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?

The description clearly states the tool lists messages sent by this runtime whose fate is unsettled (in flight or unknown). It uses a specific verb ('list' implied by 'Messages this runtime sent') and resource, and distinguishes it from other messaging tools by focusing on pending/unknown status.

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 explicitly says when to use this tool: when you need to know about messages whose fate is not settled. It also gives a clear exclusion: 'Unknown does not mean undelivered' and advises not to resend without saying so. This is strong guidance for an agent deciding whether to retry.

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