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

The description goes well beyond the annotations. While annotations declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, the description adds critical behavioral context: it recomputes the price from actual configuration, returns a price breakdown plus pricing-equation variables, compares against stored quotedPrice to flag staleness, and warns that individual variables may be manually overridden. This is rich behavioral disclosure that the annotations alone do not provide.

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 a single dense paragraph that front-loads the core purpose and then provides necessary detail about overrides and reconciliation. It is not overly long given the complexity of the tool's behavior. It could arguably be split into clearer sections, but every sentence earns its place and the structure is logical: purpose, behavior, caveat, reconciliation guidance, alternative.

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 tool with one parameter, no output schema, and rich behavioral complexity, the description is remarkably complete. It explains what the tool does, what it returns, how to interpret the results, how to reconcile against other tools, and when to use a different tool. There is no obvious missing information that an agent would need to call this tool correctly.

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 schema already provides 100% coverage for the single parameter requisitionId, including a description of how to query it. The tool description doesn't need to add much parameter-level detail. It does add context by explaining that the requisition is an existing order line, which reinforces the parameter's meaning. Since the schema covers the parameter fully, a baseline of 3 applies, and the description's contextual reinforcement earns a 4.

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 opens with a specific verb and resource: 'Explain why an existing requisition (order line) costs what it does.' It then distinguishes itself from the sibling generateQuote by explicitly stating that hypothetical/what-if parts should use generateQuote instead. This makes the tool's purpose unmistakable and clearly differentiates it from related tools.

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 provides explicit guidance on when to use this tool versus alternatives. It states that for hypothetical or what-if parts, one should use generateQuote instead. It also gives a detailed reconciliation workflow, telling the agent to examine variables against describePricingEquationApi(includeSource=true) and query materialPrices. This is exactly the kind of when-to-use and how-to-use guidance that helps an agent select and invoke the tool correctly.

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