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

With no annotations, the description carries the full burden and does well: it discloses the authentication requirement, that each run is a normal paid job bounded by max_price_cents plus delegated spending limits, and the 60-10080 minute cadence bound, with the 'rejected rather than overspending' behavior made explicit. It stops short of stating what happens to the watch on failure or partial-run outcomes, so it is strong but not exhaustive.

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 sentences, front-loaded with the purpose, then cost/cadence constraints, then the sibling routing rule. Nearly every clause earns its place; the 'Authenticated:' prefix is a slightly abrupt lead-in but still useful.

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 seven-parameter mutation with a nested constraints object and no output schema, the description covers purpose, prerequisites (auth), cost bounding, cadence limits and sibling routing. The remaining gap is the absence of any hint about the created watch's identifier/return, which is minor given no output schema is declared.

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 all seven parameters are already documented in the schema, establishing a baseline of 3. The description reinforces cost semantics (per-run cap plus delegated spending limits) but adds no syntax or format detail beyond what the schema provides.

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+resource ('create a new recurring paid watch') and the use case (repeated research or monitoring). It explicitly differentiates itself from set_recurring_paid_watch and submit_paid_machine_job, so an agent can route correctly 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?

Gives explicit when-to-use ('only to create a new watch') and names both alternatives with their own conditions: set_recurring_paid_watch for enable/disable of an existing watch, submit_paid_machine_job for one-time work. Nothing is left to inference.

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