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

Annotations already cover readOnly/idempotent/non-destructive, but the description adds substantial context beyond them: 1-hour caching (<5ms cache hits), $0.02 per call, first 5 calls free per agent_id, failed calls never charged, and the non-fatal payment-required quote with retry instructions. This is rich behavioral disclosure. Minor deduction only because the free-trial/pricing facts are restated across two paragraphs rather than stated once.

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 purpose, then clearly delimited WHEN TO USE / WHEN NOT TO USE / PARAMETER INTERACTIONS / pricing / example sections, so it is easy to scan. It is somewhat long and the free-call and per-call pricing facts are repeated in the pricing paragraph after already appearing under PARAMETER INTERACTIONS, which is the only real waste.

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?

An output schema exists, so return-value documentation is unnecessary. Given three parameters, a billing gate, and a retry-on-payment flow, the description covers everything an agent needs: inputs, cost model, failure mode, and recovery path.

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% and each parameter is already documented, so the baseline is 3. The description goes further by explaining the interaction between parameters: pass ticker as a non-empty string, omit agent_id/tx_hash during free trial calls, or supply agent_id (agd_pass_...) / tx_hash for paid execution — guidance the schema only implies separately per field.

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?

Opens with a specific verb and resource: 'Resolves all 10,000+ US public stock tickers to SEC CIK numbers, recent 10-K/10-Q/8-K filings, and entity metadata.' The scope and returned entity types are concrete, and the sibling (get_agent_wallet_status) is explicitly named as a different concern (quota/billing), so an agent can route correctly.

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?

Contains explicit WHEN TO USE and WHEN NOT TO USE sections, names the alternative tool for quota checks, and excludes unrelated domains and binary media. The condition that selects this tool ('deterministic sec-intel analysis for ticker') is stated directly.

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