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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds modest context about scope (per-account, includes custom feeds and disabled global overrides), but says nothing about ordering, pagination, or result size.

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 front-loaded sentence with no redundant restatement of the title or annotations. Every clause contributes scope 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 zero-parameter read-only list tool with annotations covering safety, the description says enough: what is listed and what the list includes. No output schema exists, but the enumerated content (feeds and disabled overrides) adequately conveys the return contents.

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 takes zero parameters, so the baseline is 4 and the description correctly implies a full, unfiltered listing with no filtering syntax to document. There is no ambiguity about arguments.

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?

Specific verb ('List') plus resource ('news sources monitored for your account'), and it enumerates what the list includes: custom RSS feeds and disabled global source overrides. That distinguishes it from siblings like add_source, remove_source, toggle_source, and the global-source enable/disable tools.

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 implies usage (inspect the account's monitored sources) but never states when to use it versus alternatives such as list_stories or the toggle/disable tools. There are no explicit prerequisites or exclusions, leaving the agent to infer routing.

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