Get Matchup

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

With no annotations, the description carries full burden, and it excels. It discloses that points of 0.0 are ambiguous (player may not have played or scored nothing), explicitly says not to claim which, explains the status field values, and clarifies that only non-BENCH/IR slots count toward score. It also describes the full response structure including win_probability nullability. No contradictions with annotations (none present).

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 description is moderately long but each sentence adds meaningful information. It leads with the primary purpose and usage examples, then provides the response structure and caveats. It is well-organized and front-loaded, though slightly verbose in the roster field enumeration; still efficient for the complexity it covers.

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?

Given there are no parameters and an output schema exists (though not shown), the description fully explains what the agent will receive: top-level fields, team fields, roster fields, and scoring rules. It also addresses the key edge case (0.0 points) and the projection nullability. Nothing an agent needs to call this tool correctly 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?

The tool takes zero parameters, so the description has no parameter semantics to add. Per the rubric, 0 parameters gives a baseline of 4. The description correctly does not fabricate parameter details, and the schema is empty with 100% coverage.

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 exactly what the tool does: returns the current-week head-to-head matchup with live scoring. The verb 'Return' plus the specific resource ('user's current-week head-to-head matchup') is unambiguous. It also distinguishes itself by limiting to the current week, which is not covered by sibling tools like get_my_team or get_free_agents.

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?

Provides explicit use cases: 'Use this for "am I winning?", "who am I playing?", or "should I have started X?"' and adds a scope limitation ('Covers the current week only'). This gives the agent clear criteria for when to invoke this tool versus alternatives, even though it does not name siblings directly.

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