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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open world), yet the description still adds substantive behavior: free-tier cost tier, newest-first ordering, the exact emitted record format, null new_status meaning the player came off the report, and the hard history floor of 2026-10-18. That is unusually rich disclosure for a read-only endpoint and covers return shape since no output schema exists.

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 dense sentences with almost no waste; the arrow notation and parenthetical null semantics compress a lot of information efficiently. Minor ding: it opens with 'Free-tier endpoint' rather than the purpose, so the most decision-relevant information is not strictly 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?

For a simple three-parameter, no-output-schema read tool, the description supplies everything needed to call it correctly: scope, time bounds, ordering, record semantics, the history floor, and a pairing use case. Nothing material 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%, so all three parameters (days, player, sport_key) are already documented, including the 1-90 range and the sport_key enumerations. The description adds only the history start date as context for the days window; it contributes nothing beyond the schema, 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 precise resource and scope: 'every injury status change in a sport over the last 1-90 days' with the record shape (old_status -> new_status). This implicitly separates it from the sibling propline_get_injuries, which covers current reports rather than change events, but it never names that alternative or explicitly contrast the two, so it stops short of a 5.

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?

'Pair with odds history to see how lines moved on a ruling' gives a concrete analytical use case, which implies when the tool is valuable. However, there is no guidance on when not to use it, and no routing between this and propline_get_injuries for a current-snapshot need, so usage is implied rather than specified.

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