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

Annotations cover the safety profile (readOnly, idempotent, non-destructive). The description adds value beyond them by disclosing the aggregation shape and the returned fields (contract count, quarter range, distinct products) and noting read-only sourcing (FERC EQR via PUDL, Phase 1 contract-terms only). It does not cover pagination/limit behavior or result ordering, keeping it short of a 5.

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?

Front-loaded with the core identity and the reverse-relationship first, then usage, mechanism, and sourcing. Dense but every clause earns its place; the sourcing/attribution line is somewhat peripheral but legitimate provenance info.

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?

Complete for a read-only aggregation tool: it explains what is aggregated, the return shape, and provenance, and annotations cover safety. No output schema exists, but the description compensates by naming the returned fields, so nothing essential is missing.

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 coverage is 100%, so all four parameters are already documented (substring match on counterparty, quarter formats, limit default/max). The description adds no parameter syntax beyond the schema, so the baseline of 3 applies.

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+resource (aggregates FERC EQR contracts by seller) and names the exact reverse-direction sibling (eqr_contracts_search), making orientation unambiguous. It even supplies example questions the tool answers.

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?

Explicitly positions the tool as the inverse of eqr_contracts_search and states the precise question class it serves ("who sells power to X"), including why a single-table filter can't do it. This is direct when-to-use guidance tied to a named alternative.

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