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

Annotations already declare readOnlyHint, idempotentHint, and closed-world, so safety is covered. The description adds meaningful behavioral context by defining the output semantics — trust score as posterior mean, a conservative lower bound (LB10), and resolved tip counts — which is information not present in the 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?

A single front-loaded sentence that names the resource, its returned fields, and the optional filter with zero wasted words.

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 read-only list tool with no output schema, the description is nearly complete because it enumerates the returned fields and explains what the trust metrics mean. It does not mention whether the list is paginated or bounded, a minor gap given the simplicity of the tool.

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 description coverage is 100% for the single optional parameter, so the baseline is 3. The description's phrase 'Optionally filter by name' merely restates the schema and adds no matching syntax or semantics beyond it.

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 and resource ('List the sources Context Pill reads') and enumerates the returned fields (tier, trust score, LB10, resolved tips), so the agent knows exactly what it gets. Sibling tools (get_latest, search_claims) are not named or contrasted, which keeps it short of a 5.

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?

'Optionally filter by name' implies the only usage variation, but there is no explicit when-to-use guidance, no exclusions, and no comparison to get_latest or search_claims. Usage is inferable from the description but not spelled out.

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