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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely non-obvious behavioral context beyond that: the underlying rules are seasonally volatile (free transfers now roll over up to 5), so results are authoritative over model memory. It says nothing about result count, ranking, or pagination, keeping it below a 5.

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 use case and then the rationale. The long parenthetical topic list is dense but earns its place by giving retrieval-relevant vocabulary. Slightly list-heavy, but no filler sentences.

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 zero-required-param, read-only search tool with full annotation coverage and no output schema, the description supplies enough to invoke it correctly: what it searches, when to prefer it, and why freshness matters. Minor omission is guidance on using gw vs query together or what an empty result implies.

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% — both gw ('Prefer guides for this gameweek') and query ('What to look for, e.g. bench boost') are already documented in the schema with examples. The description adds no additional syntax, default, or interaction semantics between the two optional parameters, 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 (search) and resource (FPL Copilot guides) and enumerates the covered topic domains: scoring, free transfers, chips, DefCon, FDR, gameweek tips, penalty takers, fixtures. This lets an agent distinguish it from retrieval-by-id siblings like read_guide or single-topic siblings like get_penalty_takers without opening a schema.

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 triggering condition — 'Fantasy Premier League rules and how-to questions' — and an explicit anti-pattern: don't rely on model memory because rules change each season. It does not, however, contrast itself with the sibling read_guide, leaving the search-vs-read choice to inference.

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