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

Annotations already declare readOnlyHint=true and idempotentHint=true, covering the safety profile. The description adds useful content-level context (each source's nature and limitations) but does not disclose additional behavioral traits such as authentication, caching, or update behavior. No contradiction with annotations.

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 a single compact sentence with no wasted words. It front-loads the verb and resource, then appends the relevant details about nature and limitations.

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 no-parameter, read-only, idempotent listing tool, the description is complete: it states what is listed, for which system, and what the output contains. With no output schema present, the description's mention of 'nature' and 'limitations' adequately communicates the return content.

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 has zero parameters, so the schema is trivially complete at 100% coverage. The description does not need to explain parameter semantics, and it does not add misleading parameter information.

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 uses a specific verb ('Lista') and a specific resource ('as fontes públicas usadas pela ObraAberta'), and it defines the content by naming the nature categories and limitations. The sibling tools are all about projects, builders, or health, so this listing tool is clearly distinct.

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?

There is no explicit 'when to use this vs alternatives' guidance. However, the zero-parameter, unique listing purpose makes it reasonably inferable that this tool is for consulting public source metadata. The description implies usage but does not state exclusions or alternatives.

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