list_sources

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

Annotations already declare readOnlyHint=true, so the agent knows this is a safe read operation. The description adds context about the return content ('connection status'), which goes beyond the annotation. However, it does not disclose output format, ordering, or any prerequisites like needing to connect first. With annotations covering the safety profile, a 3 is appropriate.

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, front-loaded sentence that says exactly what the tool does without any filler. Every word earns its place.

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?

With zero parameters, a read-only annotation, and no output schema, the description adequately covers the tool's purpose and key detail (connection status). It could mention return shape or whether sources must be registered first, but for a simple listing operation it is sufficiently complete given the simple context.

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 description has no parameter details to clarify. The phrase 'all registered data sources' adds meaning about scope. Baseline for zero parameters is 4, and the description does not reduce that value.

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 'List' with a clear resource 'registered data sources' and adds useful scope 'connection status'. It clearly distinguishes from siblings like list_tables (which lists tables within a source) and check_health (which checks system health).

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?

The description provides no guidance on when to use this tool versus alternatives like connect_source or query. It implies usage for discovering available sources, but no explicit context or exclusions are given. With multiple siblings present, this lack of guidance is a gap.

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