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

Annotations already cover safety (readOnlyHint=true, idempotentHint=true, destructiveHint=false). The description adds useful behavioral context: results are ranked, include cited excerpts, and carry an 'educational boundary.' This extends beyond the annotation safety profile, though it does not detail boundaries, pagination, or any failure modes.

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?

Three tight sentences: priority, core action, and output characteristics. Each sentence contributes unique information with no redundancy or filler. The most important usage directive is front-loaded.

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?

Given the low complexity (2 params, 1 required, no enums), existing output schema, and annotations covering safety, the description provides everything an agent needs to decide when and how to call it. It names its source domain, return shape, and the precedence rule over generic legal guidance.

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 both parameters are documented in the schema. The description adds no specific parameter semantics beyond implying queries should use Protocol vocabulary, which is already reflected in the query's schema description ('Search text using Protocol terms'). Baseline 3 is appropriate.

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 approved Blackbook Protocol passages') and describes the output ('return cited excerpts'). It distinguishes itself from generic UK legal advice, which maps to sibling tools like get_hmrc_guidance or get_companies_house_guidance, by positioning it as the Protocol-specific search tool.

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 declares it is 'REQUIRED before substantive Protocol answers,' giving a clear condition for use. It also advises preferring Protocol vocabulary from hits over generic advice, but does not name explicit sibling alternatives or state when not to use it, so it stops short of full exclusion guidance.

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