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

Annotations carry readOnlyHint=true, so the safety profile is already established. The description adds context about what data it covers (x- extensions catalog-wide) and what dimensions it returns (publisher, document count, location, value shape), but it does not disclose pagination behavior, result ordering beyond 'sort', or whether search matches keys, purposes, or both. It discloses the provenance aspect that the OpenAPI Initiative registry lacks, which is useful context beyond annotations.

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 the core value proposition, followed by concrete search/sort affordances. Every sentence earns its place and there is no filler.

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 an opinionated read-only search tool, the description is strong: it defines scope, distinguishes from a registry, lists the added provenance fields, and states search/sort capabilities. No output schema exists, so a sentence about result format/pagination would make it complete; the slight absence of search-behavior detail keeps it from a 5.

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 only 20% — only the 'context' parameter is described in the schema. The description does not explain what 'q' accepts, what values 'sort' takes, or what pagination params mean. Baseline 3 is appropriate because the parameter names are semi-self-explanatory, but the description does not compensate for the 80% undocumented schema. It does add semantic context: 'Search by key or purpose; sort by occurrences' maps loosely to q and sort, which helps.

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?

The description is precise: 'Browse every OpenAPI x- specification extension harvested across the catalog...' It clearly identifies the resource (OpenAPI x- extensions), the action (browse/search), and what makes this tool distinct from the sibling get_extension — a catalog-wide aggregate with provenance rather than a single extension lookup.

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?

The description implies a search/browse use case with 'Search by key or purpose; sort by occurrences.' It contrasts with the OpenAPI Initiative registry to position its unique value. However, it does not explicitly say when to prefer this over get_extension or find_openapis; the browser-like framing is clear context but lacks direct exclusion/alternative guidance.

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