research_source

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

With no annotations, the description carries the burden and does well on the failure path: a blocked source returns the reason and never a substitute, so the agent knows results are never silently backfilled. It also lists the returned fields, including the per-record limitation. It omits pagination, result volume, and rate-limit behavior, keeping it below a 5.

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?

Front-loaded with the core action, then a source enumeration, then the record shape, then the failure contract. No filler sentences and no repetition of the schema.

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 read-only search tool with no annotations and no output schema, the description covers the essentials: valid sources, return-record fields, and the no-substitute failure rule. It stops just short of completeness by leaving result volume/limit semantics and any auth or rate-limit constraints unstated.

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 0% and there are no enums, so the description is the only place the valid source values (hackernews, reddit, github_issues, stackoverflow, wikipedia, youtube) are defined — without it the agent would guess at casing and naming. It adds nothing for query syntax or the meaning of limit beyond the schema default, so it compensates fully for the most error-prone parameter but not all three.

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?

"Search ONE research source and get evidence records" gives a specific verb (search), resource (a single named source), and result type (evidence records). The enumerated source list plus the emphasized "ONE" lets an agent distinguish this from multi-source siblings like research_any or research_sources.

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?

Usage is implied rather than stated: pick this when you already know the single source you want, otherwise a broader sibling. There is no explicit when-to-use/when-not or named alternative, so the agent must infer the routing rule from the capitalized "ONE".

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