postgrid_estimate_cost

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

With no annotations provided, the description carries the behavioral transparency burden. It explicitly discloses that this tool makes no API call and relies on PostGrid's published rate table, signaling an offline, read-only calculation with no side effects. It does not mention the exact return shape, but the most important safety and execution traits are disclosed.

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 two short sentences with no filler. It front-loads the core purpose and adds the key behavioral detail ('without making an API call') before mentioning the rate table.

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 simple estimation tool, the description covers the main intent and execution model, but there is no output schema and no mention of what the tool actually returns (e.g., currency, amount, breakdown). The parameter constraints are documented in the schema, so the main missing piece is return-value context.

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 input schema already provides 100% parameter coverage with descriptions, defaults, and the enum for type, so the baseline is 3. The description adds no parameter-specific meaning; it even uses 'check' while the schema enum is 'cheque', which is a minor terminology mismatch. The schema itself remains the reliable source for parameter details.

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 ('estimate') and a clear resource ('cost of sending a letter or check'), and distinguishes this tool from every sibling by specifying it works 'without making an API call'. This makes the tool's unique purpose immediately identifiable.

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 implies a clear use case: retrieving a cost estimate before actually sending a letter or check, without incurring an API call. It does not explicitly name sibling tools like postgrid_create_letter or postgrid_create_cheque as the alternatives for actual sending, but the context is clear enough for an agent to route correctly.

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