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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds that the list covers two source types (editorial and RSS), which is mild behavioral context, but says nothing about whether the list is static, cached, or how it changes.

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 phrase with no filler. Every clause (public, editorial/RSS, accepted by cbc_headlines) carries 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?

An output schema exists, so return values need not be explained. For a zero-param enumeration tool with read-only annotations, the description supplies the essential facts: what the list is and what consumes it. It could still note whether the values are slugs/IDs.

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; there is nothing for the description to compensate for, and no parameter semantics to add.

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 names the resource precisely (CBC News public editorial or RSS sections) and ties it to the sibling cbc_headlines, letting an agent distinguish it from cbc_article/cbc_news/cbc_author. The verb is implicit (this is a no-arg enumeration returning valid section identifiers) rather than stated, which keeps it just short of 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?

It implies usage by stating the sections are 'accepted by cbc_headlines', so an agent can infer this is a discovery/lookup step feeding that tool. However, it never says when to call it, whether it should precede cbc_headlines, or any alternative for resolving sections.

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