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

With no annotations, the description carries the behavioral burden and does well: it discloses the trial allowance and duration, the idempotent non-resetting behavior on repeat calls, and that a signing_secret is returned for verifying RunLater-Signature on deliveries. What's missing is any mention of auth/permission requirements or error behavior.

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 tight sentences, front-loaded with the action and its outcome, followed by call-timing semantics and then the return-value note. Nothing is redundant and no sentence could be dropped without losing information.

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 zero-parameter tool with no output schema, the description covers what an agent needs: what gets created, the trial limits, idempotency, and the key returned field. The full shape of the returned project object is not described, a minor gap given there is no output schema.

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 tool takes zero parameters, so the baseline is 4; there is no parameter meaning to add. The description correctly implies the project is inferred from the calling agent rather than passed in.

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?

States a specific verb and resource ('Create ... AgentLater project') plus the concrete scope of the result (free trial with 1,000 delivery attempts, 7 days). 'Create' cleanly separates it from the sibling get_project, and the trial terms make the outcome unambiguous.

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?

Gives clear timing guidance — 'Call once before scheduling' — which tells the agent where this sits in the workflow. It also preempts the most likely misuse by stating a repeat call returns the same project and never resets the trial. It stops short of naming an alternative sibling or stating failure conditions, so not a full 5.

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