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

With no annotations, the description carries the behavioral burden and does so well: it discloses rate limits (one call per caller, 100 per UTC day), that limits fail closed, and the nature of the output (citation count and cited domains). This is meaningful behavioral context beyond the schema.

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 two sentences with no waste. It front-loads the core action and output, then adds the critical rate-limit behavior, and closes with the usage context relative to the paid sibling.

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?

For a two-parameter tool with no output schema and no annotations, the description covers the main behavior, output elements, limits, and failure mode. It lacks a defined response format but gives enough for an agent to call it and interpret the result generally.

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 schema covers 100% of the parameters with descriptions, so the baseline is 3. The tool description adds little about parameter semantics beyond referencing 'target domains', but the schema already documents prompt and targets thoroughly.

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 states a specific verb and resource: it sends one prompt to Perplexity (sonar) and reports whether target domains are cited, along with citation count and cited domains. It also distinguishes itself from the sibling citation_tracker_check by positioning this as a free live evaluation before paying.

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?

The description gives clear usage context: this is a free, real live evaluation to use before paying for citation_tracker_check. It implies the alternative (the paid check) and the condition for choosing this tool, though it does not explicitly enumerate when not to use it or contrast with citation_tracker_shortlist_gate.

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