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

Beyond the readOnly/openWorld/idempotent annotations, the description discloses token-matching semantics (word-start only, never mid-word), that parent ATT&CK techniques include recorded subtechniques, that CWE mappings are exact with no hierarchy expansion, that Deprecated/Obsolete records are excluded by default, and the precise result ordering. It even warns that mappings are incomplete and do not validate current ATT&CK coverage — a real caveat an agent needs.

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 search surface and back-loaded with ordering and paging guidance, with no filler sentences. It is somewhat dense and restates the word-start token rule that the filter parameter schema already documents, a minor redundancy.

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 9-parameter search tool with an output schema, the description covers the behavioral edges an agent would otherwise get wrong: default exclusion of inactive patterns, no hierarchy expansion on CWE, incomplete mappings, deterministic ordering, and cursor continuation. Nothing needed to call it correctly 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 baseline is 3; the description adds meaning on top by clarifying that CWE filters are exact-without-hierarchy and that attack-technique filters roll up parent techniques, which the schema does not say. It does not explain how to discover severity/likelihood values in the description (that hint lives only in the schema), so it stops short of a 5.

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 (search CAPEC attack patterns) plus the full set of searchable dimensions. It explicitly routes to the sibling cwe_get_attack_pattern for complete sections, so an agent can distinguish it from related tools without opening schemas.

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?

"Omit filters to browse" gives the no-filter case, "use cwe_get_attack_pattern for complete sections" names the alternative and its condition, and "follow nextCursor for remaining matches" covers the paging case. Usage is fully specified rather than inferred.

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