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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering the safety profile. The description adds useful context about the 'current indexed state' but omits return format, pagination behavior (which the cursor param hints at), and any freshness/rate-limit details. With annotations carrying the safety burden, this is adequate but not rich.

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?

Two tight sentences with zero waste. The primary purpose is front-loaded, and the usage instruction follows immediately. Nothing extraneous.

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?

Given that the tool has an output schema (which explains return values), annotations covering safety, and full schema coverage, the description needs only to state purpose and usage, which it does. It is nearly complete, missing only mention of pagination limitations or typical output shape, but the output schema likely covers the latter.

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?

Schema coverage is 100% – both parameters (limit and cursor) are fully documented in the schema, including the notable note that cursor is unsupported and the catalog does not page. The description adds no parameter details, so baseline 3 is appropriate when the schema does the heavy lifting.

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 ('List') and resource ('developer source catalog and current indexed state'), clearly distinguishing it from siblings like developer_search or research_sources. An agent knows exactly what this returns without consulting the schema.

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?

Provides clear contextual guidance: 'Use this to discover source IDs before searching the verified Go documentation corpus.' This tells the agent when to use it (prerequisite discovery step) but doesn't name the specific sibling to use afterward or state when not to use it, which would be needed for a 5.

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