epost_store_letter

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

With no annotations, the description carries full behavioral burden. It discloses the action is non-destructive, requires a folder, and addresses methods with index shift warning. Lacks details on permissions, error handling, or side effects, but adequate for a simple archival action.

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 with no redundancy. Front-loaded with core action and key differentiator (not a delete). Every sentence adds value.

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 no output schema and 4 parameters (1 required), the description covers the main behavior, identification methods, and a crucial behavioral warning (index shift). Could mention error handling or what happens if letter not found, but overall complete for intended use.

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?

Adds meaningful context beyond the input schema: clarifies that folder is required, explains how to identify letters via index or title substring, and notes indices shift. The schema covers 50% of parameters; description compensates well.

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?

Clearly states it archives a letter into a Storage folder (the 'Store' action), emphasizes it is not a delete, and distinguishes from sibling tools like epost_delete_letter.

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?

Provides clear instructions on how to address a letter (by index or substring) and warns that indices shift after each store, recommending re-listing. Does not explicitly state when not to use or compare to alternatives, but context is sufficient.

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