React to a Bluesky direct message

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

The description discloses meaningful behaviors beyond the annotations: it enforces the one-emoji rule locally, reports the reaction state as read back from Bluesky rather than the requested one, and notes it is free. These details help the agent anticipate validation and result behavior. Annotations (readOnlyHint: false, destructiveHint: false) are consistent and do not contradict the description.

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 front-loaded with the core function, then adds context about the one-emoji rule, return behavior, and cost. It is slightly wordier than necessary (e.g., 'a paragraph back would be worse than a thumbs-up') but remains efficient and well organized, with no wasted sentences.

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 mutation tool with four parameters and no output schema, the description covers the key aspects an agent needs: the action, the one-emoji constraint, the reported return value, and the cost implication. It does not mention error scenarios (e.g., invalid convoId) or authentication specifics, but these are less critical given the schema and annotations.

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 schema provides full descriptions for all four parameters, including exactly-one-emoji guidance for value and the toggle behavior for remove. The tool description reinforces the one-emoji rule but adds no new parameter-level details beyond what the schema already covers, so it sits at the baseline for high schema coverage.

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 and resource: add or remove an emoji reaction on a single Bluesky DM. It distinguishes the tool from sending a reply by framing it as a light acknowledgement, but it does not explicitly mention sibling tools like send_bluesky_dm or read_bluesky_dm, so it stops short of full differentiation.

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 provides concrete usage context: use this for quick acknowledgements like a 'thanks' where a written reply would be excessive. It implies when not to use a text reply but does not explicitly name an alternative tool or state conditions that rule it out, so the guidance is useful but not exhaustive.

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