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

Beyond the readOnlyHint/openWorldHint annotations, it discloses concrete operational traits: exactly one external page fetch per call, a $0.002 USDC metered cost per successful call, x402 payment on Base/Solana/Arc, and that failed calls are not charged. Cost and payment-rail disclosure is exactly the kind of information structuring fields cannot convey for a paid, open-world lookup.

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?

Two sentences, front-loaded with what is returned, then scope limits, then pricing. No filler; every clause carries information an agent needs before invoking.

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 single-parameter, read-only, paid lookup with an output schema present, the description covers purpose, exclusions, call granularity, and billing — everything needed to call it correctly. Return-value structure is legitimately left to the output schema.

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 the single parameter already documents the ID format (T1059 / T1059.001). The description's inline example adds only marginal confirmation of the sub-technique form and reiterates that the sub-technique list is not returned, so the baseline 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 and resource — 'looks up one MITRE ATT&CK technique ... on its official public page' — and enumerates the returned fields (name, tactic-level summary, page title). It explicitly bounds scope ('does not return the whole matrix or a technique's sub-techniques list'), which separates it from every sibling security_* tool that targets DNS/IP/reputation data.

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 when-not guidance: one page per call, no whole-matrix retrieval, no sub-technique enumeration, so an agent knows to make separate calls per ID rather than expect bulk data. It stops short of naming an alternative tool for matrix-wide or sub-technique needs, so it is strong context without explicit routing.

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