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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the description needn't restate that. It adds genuinely useful context beyond the structured fields: the model is a free Dixon-Coles variant distinct from the premium app model, and it imposes an agent obligation to cite source, model, and calculation date.

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?

The return contents are front-loaded and the sourcing instruction follows; every sentence carries information. The parenthetical aside about the paid model is slightly wordy but earns its place by preventing model confusion.

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?

With no output schema, the description usefully enumerates the returned markets, xG, exact scores and team strengths, and it supplies the match_id source and citation requirement. It is essentially complete for a single-argument lookup; only rate limits or summary/notice behavior remain 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 description coverage is 100%, so both parameters (match_id, lang) are already documented, and the description only reinforces the match_id provenance. No added meaning for lang or any format/validation detail, so this sits at the baseline for a fully-covered 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?

Specific verb ('Returns the probabilities') plus a scoped resource ('one football match') and an explicit enumeration of what is returned (1X2, over/under, BTTS, xG, exact scores, team strengths). It also distinguishes itself from a similarly named model (the free Dixon-Coles vs. the Docteur Bet model reserved for value bets), so an agent can tell it apart from siblings like get_season_projection or get_team_strengths.

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?

Explicitly tells the agent where match_id comes from ('find_match or get_upcoming_matches'), which routes the caller correctly and implies this tool should be called after a lookup. It does not state when NOT to use it or contrast it against get_season_projection/get_team_strengths, so it stops short of full alternatives guidance.

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