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

The description discloses critical behaviors not expressed in the annotations: the run is billed from the caller's credits, it is asynchronous ('poll runs.get until completed'), and it performs real external work. The openWorldHint only weakly implies external action, so the descriptive detail adds substantial transparency. No contradiction with readOnlyHint=false or destructiveHint=false.

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 one dense paragraph that front-loads the action and billing, then gives lifecycle instructions and mode guidance. Every clause contributes operational value, and there is no redundant restatement of the schema.

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 output schema covers the return record shape, so the description focuses on what structured fields cannot convey: the async polling workflow, the follow-up report step, billing consequences, and special input formats. An agent has enough context to invoke this tool correctly and continue the workflow.

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?

Although schema coverage is 100%, the description adds a concrete list of supported mode values (research, news, product, trips, trainer, finance, astrology, horoscope) that the schema lacks because there is no enum. It also enriches the input parameter by explaining constraint-line syntax for astrology/horoscope and linking to the full contract, materially improving invocation correctness.

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 uses a specific verb and resource ('Launch a run') and explains exactly what a run does: agents search the web, read sources, and produce a cited report. It clearly distinguishes this from sibling tools by framing it as the start of a workflow that continues with runs.get and runs.report.

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 gives clear post-launch guidance: poll runs.get until completed, then runs.report. It also lists modes and points to an external contract for special input constraints. It does not explicitly state when not to use this tool or compare alternatives like route.classify, but the lifecycle and context are strong.

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