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

Beyond the annotations (readOnlyHint false, destructiveHint false), the description explains the important interaction model: the tool opens a UI, the user finishes there, and only on submit does it create the post via create_post. It also discloses pre-fill behavior and connected-channel display. Minor omission: no statement about cancellation or how scheduling is completed, but the output schema covers return expectations.

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?

Two sentences, front-loaded with the action and immediate behavioral context, and the routing guidance is delivered in a single clause. No filler or repetition of schema 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?

For an interactive compose tool, the description covers what the tool does, how the user flow completes, what happens on submit, and when to prefer it over create_post. Combined with a full schema and an output schema, nothing essential is missing for an agent to invoke or route to it.

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 input schema already fully documents content as 'Optional initial text to pre-fill the composer with' (100% coverage). The description's 'pre-fills any provided text' restates that without adding syntax, defaults, or constraints, so the description adds no significant meaning beyond the schema.

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 names a specific action (open an interactive composer), the resource (a social media post), and the scope (draft or schedule, choose from connected channels, pre-fill text). It explicitly differentiates from the sibling create_post by framing this as the interactive, review-first path, so an agent can distinguish them without opening schemas.

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?

Ends with explicit routing guidance: 'Use this when the user wants to compose a post interactively in a UI — prefer this over create_post when they'd review before posting.' This names the alternative tool and the condition that selects compose_post over it.

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