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

No annotations are provided, so the description carries the full behavioral burden. It implies a read-only listing operation but discloses nothing about permissions, scope of "external" sources, pagination, volume, or result format. For a tool with zero structured behavioral coverage this is thin.

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?

A single short sentence with no waste and the purpose front-loaded. It is efficient, but the brevity reflects under-specification rather than disciplined packing of useful information.

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 simple one-optional-parameter list tool with complete schema coverage and no output schema, the minimum is nearly met. Still missing are the boundary against sibling list/search tools and any note on what a returned "source" contains, which matters given the crowded sibling set.

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 single optional parameter "query" is fully documented in the schema (100% coverage), so the schema does the heavy lifting. The description adds nothing about how filtering behaves (matching semantics, empty query behavior), so baseline 3 applies.

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 clear verb ("Lista") and enumerates content types ("registros externos, catálogos e matérias públicas"), so the general purpose is inferable. However, the term "fontes"/"sources" is broad and the description gives no hint of how this differs from the many sibling list_* tools (list_books, list_themes, list_rights_opportunities). It is adequate but not sharp.

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 when-to-use guidance, no named alternative, and no condition under which an agent should prefer list_sources over search_books, list_books, or ask. The agent is left to infer the trigger entirely.

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