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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful context beyond that: the return shape is enumerated (title, link, published, summary) and items are described as 'normalized', which tells the agent what to expect from the response.

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 tightly packed sentences with zero filler: the first covers the primary operation and id source, the second covers return content and the optional filter. Information is front-loaded and nothing is redundant.

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 no output schema, the description carries the burden of describing returns and does so by enumerating the normalized item fields. The feed id provenance, filtering option, and return shape are all covered, leaving only minor gaps such as pagination or rate-limit behavior.

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%, so every parameter (feed, limit, query) is already documented in the schema, including the 1-50 range and default of 20. The description only restates the optional keyword filter and the id provenance, adding no syntax or meaning beyond the schema; baseline 3 applies.

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 ('Read a curated transport & mobility feed by its id') and names the domain coverage. It distinguishes itself from list_feeds by requiring an id sourced from that tool, but it does not distinguish itself from the sibling fetch_feed, leaving some ambiguity between the two feed-reading 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 parenthetical '(from list_feeds)' implies a prerequisite workflow, and 'Optionally filter items by keyword' hints at the query case. However, there is no explicit guidance on when to choose this over fetch_feed, nor any stated exclusions or limits on usage.

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