List Letters

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

The description adds meaningful behavioral context beyond the annotations by explicitly stating that unpublished letters are included and that full letter records are returned as JSON. This provides useful details not covered by readOnlyHint, idempotentHint, or destructiveHint.

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?

The description is two concise sentences that directly state the action, scope, ordering, and return format. Every word earns its place, with no redundancy or irrelevant details.

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?

Given the tool's simplicity, no output schema, and complete annotations, the description fully covers the essential aspects: what is returned (full letter records as JSON), ordering, and inclusion of unpublished items. This is sufficient for a parameterless list operation.

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, and the description correctly avoids unnecessary parameter explanations. Since schema coverage is 100% (void), the baseline of 4 applies, and the description adds sufficient clarity about the operation's output.

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The description clearly states the verb (list), resource (Playbook letters), and scope (all letters, including unpublished), and specifies ordering (newest first). This distinguishes it from sibling tools like get_letter (single letter) and other list_* tools for different resources.

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 context of use is implied by the clear purpose (use this to get all letters), but there is no explicit mention of when to use alternatives like get_letter for a single letter. No exclusions or alternative references are provided, so the guidance is implicit rather than explicit.

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