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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds the FCI score interpretation scale, which is useful domain context, but says nothing about pagination, rate limits, or result ordering beyond what the schema notes about automatic page fetching.

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 purpose before the interpretive scale. Every sentence carries information, though the scoring band breakdown could be trimmed or deferred without loss.

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?

No output schema exists, so the description usefully supplies the score interpretation bands that the agent needs to make sense of FCI values. For a read-only list tool with fully documented parameters, this is close to sufficient; only the returned record shape and pagination semantics remain undocumented.

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 all three parameters (page, per_page, site_id) are self-documented including the auto-pagination behavior and the 1000-item cap. The description adds no parameter-level detail, so the 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 (List) and resource (FCI history for sites) and expands the FCI acronym, so the agent knows exactly what data comes back. It does not, however, explicitly contrast itself with the sibling get_site_fci_history_entry, leaving the singular-vs-collection distinction to be inferred from the verb alone.

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?

'Track FCI trends over time' implies the usage context (trend analysis across multiple points), but there is no explicit when-to-use guidance, no exclusions, and no direction toward the alternative get_site_fci_history_entry for a single record. Usage is implied rather than stated.

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