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

Annotations already declare a read-only, open-world lookup, and the description adds real behavioral context beyond that: results preserve source ids, source ordering, repeatability flags, and nullable values, and prices are 'published' rather than computed. The negative scope clauses clarify what the call will never do. It stops short of any note on failure behavior when a slug is unknown.

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 short sentences, front-loaded with the core action and return payload, then the slug sourcing rule, then exclusions. Slightly redundant because the EA-id/database-id caveat appears in both the description and the schema, and the trailing 'no biography' clause feels like boilerplate.

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 one-parameter read with an output schema and read-only annotations, this covers the essentials: what it returns, how to obtain the key, and what fidelity guarantees apply. Nothing an agent needs in order to invoke it correctly is missing, though error/empty-result behavior is unstated.

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% and the single `slug` parameter is fully documented, including the example and the EA-id prefix rule. The description repeats that same prefix rule and adds only the marginal hint that the value should be copied verbatim from a listing row, so it adds little beyond the schema.

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 (read one FC27 SBC set), names the lookup key (source slug), and enumerates what comes back (set, challenge, condition/reward metadata with published prices). The 'by its source slug' framing plus the EA-id-vs-database-id note separates it from the sibling setters (`futgg_fc27_sbc_set_by_challenge`, `futgg_fc27_sbc_set_by_ea`) and the list 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?

Gives an explicit acquisition path: take the slug verbatim from a `futgg_fc27_sbc_sets` row, which tells the agent to list first, then fetch. It also rules out three things not to expect (solver execution, private club access, biography), but it never names when to prefer `sbc_set_by_challenge` or `sbc_set_by_ea` instead, so the alternative-selection guidance is incomplete.

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