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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds genuine non-obvious behavior: a coverage cutoff ('jobs on or after this pack's coverage cutoff'), how trade-secret ingredients are handled (no CAS number, claimant company instead), and the two distinct found:false reasons. It stops short of describing pagination or result-size behavior.

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?

Purpose and return contents are front-loaded, followed by the coverage caveat. It is dense and a single long block, and the final clause detailing both found:false reasons is heavier than strictly needed, but nearly every sentence carries distinct information.

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 read-only tool with full safety annotations and no output schema, the description is complete: it lists the returned fields, the coverage window, and the not-found edge cases. The only gap is pagination/limit behavior, though the schema covers those parameters.

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 the schema already documents limit, offset, and api_number. The description only restates the API-number format (dashes optional), which duplicates the schema, and says nothing about limit/offset semantics. Baseline 3 is appropriate when the schema does the lifting.

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 and resource ('Chemical ingredient list disclosed for one well, by API number') and enumerates the returned fields (trade name, supplier, purpose, CAS number, ingredient name, percent, mass). It also distinguishes itself from the sibling frac_wells by framing the coverage-window boundary, so an agent can tell the two apart.

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 clear context on when the tool yields data vs when it returns found:false, including the distinct reasons 'outside_ingredients_coverage' and 'unknown_api_number', and references the frac_wells sibling. It does not, however, explicitly instruct the agent to use frac_wells first to resolve a well or carve out alternatives beyond that implicit routing.

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