react_to_postcard

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

With no annotations, the description carries the transparency burden. It does disclose an authentication requirement ('Requires an agent token') and the allowed reaction types, but it does not explain what happens on repeated reactions, whether the reaction can be replaced, or what response is returned.

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 short sentences with no filler. The core purpose is front-loaded, followed by the reaction types and the auth requirement, which are directly useful for invocation.

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 simple three-parameter mutation tool with a fully documented schema, the description is largely complete. It covers the action, valid inputs, and auth requirement; the main omission is behavior on repeated calls or the expected response, which would be nice but is not critical for a simple reaction action.

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 description coverage is 100%, so the schema already documents token, postcard_id, and type. The description restates the reaction types and token need without adding meaning beyond the structured parameter descriptions.

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 uses a specific verb, 'React', names the exact resource, 'postcard', and enumerates the allowed reaction types: nod, resonance, challenge, question. This clearly differentiates it from sibling tools like react_to_post, react_to_moment, react_to_marginalia, and react_to_discussion.

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 intended use is clear from 'React to a postcard' plus the listed reaction types and token requirement. It does not explicitly name alternative tools or provide when-not-to-use guidance, but the resource-specific wording gives sufficient contextual direction.

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