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

Annotations already declare readOnly/idempotent/non-destructive, yet the description adds operational context the annotations cannot convey: stateless edge call, 32 KB cap, 60 RPM limit, demo mode, L402 payment of 10 sats, and an HTTP 400 on invalid input. That is unusually rich disclosure of cost, throttling, and failure behavior.

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?

Purpose and the sibling routing come first, which is the right front-loading. The final sentence compresses six distinct facts (stateless, size, rate, default, auth, error code) into one dense clause, which is efficient but borders on cramming and could be easier to scan as discrete points.

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?

An output schema exists, so return values need not be described. Between the purpose, the alternative routing, the payment/rate/error behavior, and full schema coverage, an agent has everything needed to decide and invoke correctly.

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 coverage is 100%, so the baseline is 3, but the description contributes the default for 'authority_metric' ('pagerank_and_domain_authority') that the schema does not state. It also frames 'subject_area' as an academic field, open source framework, protocol, or discipline, which slightly sharpens the schema's wording rather than merely repeating it.

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 a specific verb and resource ('Identifies and ranks top domain authorities, leading researchers, and primary documentation repositories') scoped to technical topics. It also names the sibling it is not (synthesize_neural_search) for the adjacent use case, so an agent can discriminate between the two without opening a schema.

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?

Explicit when-to-use cases ('finding primary source experts to cite or discovering foundational documentation for specialized fields') plus an explicit when-not and named alternative ('for ranking general search query snippets, use synthesize_neural_search instead'). Nothing is left to inference.

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