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

The description goes well beyond the annotations (readOnlyHint, openWorldHint). It adds that the tool is computable from 'ARES + ISIR data alone', returns a 'PhoenixReport with riskScore 0-100', and requires a 'Pro Compliance tier'. These are important behavioral details not present in annotations.

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, each with a distinct role: purpose/indicators, output/access, and alternative. No fluff or repetition. The information is front-loaded and every clause earns its place.

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 detection tool with several indicators and an output riskScore, the description covers the essential context: input (ICO), computation (3 indicators, data sources), output (PhoenixReport with riskScore), tiers, and a pointer to the richer version. It does not explain the interpretation of the riskScore or the structure of PhoenixReport, but given no output schema, this is a minor gap.

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 only parameter 'ico' is fully documented in the schema ('Czech IČO — 7 or 8 digits') with 100% coverage. The description does not add any additional meaning about the parameter itself, so the baseline of 3 applies as the schema carries the weight.

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 states the tool's purpose: 'Detect phoenix company pattern' and lists exactly what it computes (3 surface indicators). It also distinguishes itself from the sibling tool detect_phoenix_rich by specifying the limits of surface indicators vs deep indicators, making its role 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?

Explicit guidance is provided: 'Pro Compliance tier or higher' states an access requirement, and 'For 4 additional deep indicators ... see detect_phoenix_rich' directly names the alternative and when to use it instead. This gives the agent clear decision criteria for tool selection.

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