source_check

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

Beyond the readOnlyHint and openWorldHint annotations, the description fully discloses behavior: no LLM involvement, extraction from user-provided or search-found sources, lexical scoring with negation handling, possible verdict categories, use of cache, and the refresh flag to bypass caching. This is rich and accurate context.

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 organized with a clear summary first, then behavior, then a compact Args list. Every sentence adds value, and no information is repeated from the schema. It is detailed without being bloated.

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 the tool's moderate complexityched, the description is complete: it explains the deterministic method, verdict types, source selection behavior, all parameters, and the appropriate use case. The output schema exists, so return-value details do not need to be repeated in the description.

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 0%, but the description compensates fully by documenting all four parameters in the Args block. It adds constraints not present in the schema (e.g., urls 1-10, max_sources 1-10, refresh meaning) and clarifies supported languages for claim.

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?

The description opens with a specific verb and resource: 'Deterministically verify a claim against web sources; return a verdict with quoted passages.' It also distinguishes itself from siblings by emphasizing reproducibility, lexical scoring, and verdicts rather than narrative or open-ended research.

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?

It explicitly states the intended use case: 'Best for checking a fact, assertion or rumour when you need a reproducible verdict with citations, not a narrative.' It also explains when to supply URLs versus rely on web search. It does not name sibling tools explicitly, but the 'not a narrative' exclusion gives clear decision context.

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