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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description adds genuine unannotated context: it can be called without an account/OAuth, and it self-documents rate limits and connection flow rather than requiring another call. It stops short of describing output shape or size, which for a large meta payload would have been useful.

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 statement, then the contents list, then the usage directive — good ordering. The space-separated bilingual block appended after '/' adds length an English-only agent must skip, slightly diluting density.

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?

There is no output schema, so the description must carry the return-value burden, and it does: it enumerates the response sections (data, tools, units, defaults, auth, rate limits, examples). Combined with the no-auth caveat, an agent has everything needed to decide to call it and what to expect.

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?

Single optional `language` enum with 100% schema coverage, so the schema does the work and baseline 3 applies. The description's bilingual EN/PT text implicitly signals language support but never names the parameter or its default explicitly — a small missed opportunity.

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?

Opens with a specific verb+resource ('Returns a factual overview of this connector') and enumerates exactly what the payload contains: data sources, tool list with usage, units, defaults, auth method, rate limits, example questions. This clearly distinguishes it from the ~40 analytical siblings, which all answer specific SEO questions rather than describing the server itself.

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 routing instruction: 'Use it first when you do not know what this server can answer.' It also states the pre-condition that matters most for a discovery tool — 'Works without signing in' — so an unauthenticated agent knows it is still callable.

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