sendChatAction

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It usefully discloses the 5-second timeout, the clearing behavior upon message arrival, and the success return value. It does not describe failure behavior, but this is a minor gap for a simple fire-and-forget 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 short sentences, each contributing useful information: the core purpose, the timeout/clearing behavior, and the return value. There is no redundant or filler content.

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?

The description is largely complete for a simple tool with fully documented parameters and no output schema. It covers the key behavioral constraints and return value. An explicit note about pairing this call with a subsequent message send would make it fully complete, but nothing critical is missing.

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 parameters are already well documented in the schema. The description adds no additional parameter-level meaning beyond the schema, which matches the baseline for full 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 identifies the tool as a way to signal bot-side activity to the user, which is distinct from content-sending siblings. However, it relies on the vague phrase 'something is happening' and does not explicitly name or contrast itself with any sibling tool.

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 timing details—status set for 5 seconds or less and cleared when a message arrives—provide clear practical context for when the tool should be invoked. It stops short of explicitly stating 'call this right before sending a message' or naming exclusions, but the intended usage is strongly implied.

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