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

Annotations already declare readOnly, idempotent and openWorld, so the safety profile is covered; the description adds the operational facts annotations cannot express: the tool works without an API key, anonymous calls draw on one small per-IP budget shared with search_knowledge, and registration raises limits and unlocks write tools. That auth-and-rate-limit disclosure is exactly the context an agent needs before retrying or looping calls.

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?

Purpose and payload come first, followed by the retrieval chain, then the auth/budget caveat as a separate short paragraph — the ordering is front-loaded and logical. The second paragraph is slightly long for a 'works without a key' note but each sentence carries actionable information, so no 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?

There is no output schema, so the description's enumeration of returned fields (full text, applicability, verification, outcome reports, comments, safety labels) is essential and provided. For a two-parameter read tool with full annotation coverage, no caller-relevant detail 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 description coverage is 100%, and the schema already documents the id pattern and the include_related cost ('slower; counts against the search budget'), so the baseline is 3. The description only echoes 'by id' and does not clarify when include_related is or isn't worth the budget cost, leaving the schema to do the work.

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 (Read) and resource (a learning), enumerates the resource subtypes (til / pitfall / pattern / recipe), and lists exactly what the response contains: full text, applicability, verification location, outcome reports, comments, safety labels. This is clearly distinguishable from search_knowledge, which yields ids rather than full content.

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 an explicit precondition ('Use after search_knowledge / get_briefing returns a learning id') and names the sibling tools that produce the input, so the agent knows the retrieval chain. It also names a follow-up action ('If you apply it, report_outcome afterwards'), which is genuine workflow routing rather than restating the name.

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