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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety bar is low. The description adds genuinely useful behavior the annotations cannot: the "outcome is null while fewer than 20 players have predicted" threshold, which is a non-obvious data-availability rule. It does not describe ordering, limits, or pagination for the list form.

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?

A single front-loaded sentence defines the payload, followed by the two invocation shapes and the null-outcome caveat. Every clause carries information an agent needs; nothing is restated from the schema or annotations.

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 must carry the return shape — and it does, naming the crowd shares, top scores, player bands, and expert cohort plus the null-outcome case. Missing is any hint of list-mode size, ordering, or pagination, which matters for a filter-driven list call.

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% with enum descriptions, so the baseline is 3. The description goes beyond it by stating the id-vs-filter branching (single record vs list) and by tying "most likely score" to the National mode, clarifying how mode changes the payload rather than just filtering it.

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?

Specific verb+resource: it enumerates exactly what a full prediction record contains (home/draw/away shares, top 3 exact scores, player bands, expert cohort). It never names or contrasts itself against the visible siblings get_match_prediction, find_matches, or list_matches, so the agent must infer the boundary itself.

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?

"Pass an id for one match, or mode/status filters for a list" gives clear invocation guidance for the two call shapes, and the schema confirms filters are optional. But there is no when-to-use vs when-not guidance, and no routing to get_match_prediction (lighter prediction) or find_matches/list_matches for discovery, which are the obvious alternatives.

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