top_sources

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

With no annotations, the description carries the full burden for behavioral disclosure. It does reveal the exact result JSON, including the dimension key 'visit:source' and metrics 'visitors' and 'bounce_rate', but it does not state read-only behavior, sort direction beyond the word 'top', or possible failure modes.

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 exceptionally compact: a one-line purpose statement followed by a concise JSON example that shows the exact response structure. There is no verbosity or redundant information; every word earns its place.

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?

Despite lacking an output schema and annotations, the description compensates with a concrete result example, and the fully-covered parameter schema handles invocation details. Some ambiguity remains around what 'visitors' counts and no usage context is provided, but the essential calling information is present.

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 the site, limit, and period parameters are already thoroughly documented. The tool description adds no parameter-level meaning beyond the example output shape, so the baseline score of 3 is appropriate.

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 clearly identifies the resource ('traffic sources for a site') and the ordering metric ('by visitors'), and the example return shape reinforces what is retrieved. However, it uses a noun phrase rather than a verb and does not differentiate from sibling tools like top_pages or top_countries.

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?

No guidance is given about when to choose top_sources over siblings like top_pages, top_countries, or query_stats. The description only states the general purpose; there are no alternatives named or conditions for exclusion.

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