get_schema

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

With no annotations, the description carries the full behavioral burden and does well: it discloses the dependency ordering (must precede the first query and follow every switch_source) and the volatility of the payload (fields change from source to source). It omits error behavior, caching, and cost, but the core operational traits are covered.

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?

Three tight sentences, front-loaded with what is returned before the imperative instruction. Every clause adds information: payload contents, call timing, and the reason (fields differ per source). No filler.

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 zero-parameter tool with no output schema, the description compensates by enumerating the return contents (name, typed fields, queries, examples) and the mandatory call timing. An agent has everything it needs to invoke this 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?

The tool takes zero parameters, which is the baseline-4 case; there is nothing for the description to disambiguate. Schema coverage is trivially complete, so no compensation is needed.

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 ('Devuelve') and resource (the ACTIVE source's schema), and enumerates exactly what the return contains: source name, typed fields, available queries, and examples. It also anchors itself against the sibling switch_source, so an agent can place it in the workflow without opening another definition.

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?

Gives an explicit, emphatic trigger: call before the first query and every time switch_source is used. That is unusually actionable sequencing guidance. It stops short of naming when NOT to use it or pointing to alternatives such as list_sources, so it falls just short of a 5.

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