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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint false. The description adds valuable behavioral details: filtering, deduplication, time-ordering, and bounded partial-failure reporting. It complements the annotations without contradiction, providing a clear picture of runtime behavior.

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?

The entire description is a single sentence of about 20 words. It is front-loaded with the verb 'Merge' and packs essential constraints ('two to eight', 'public'), transformations ('filtered, deduplicated, time-ordered'), and a distinguishing edge behavior ('bounded partial-failure reporting'). No filler 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?

The tool has 6 parameters and 0% schema coverage, yet the description provides a solid conceptual model: input is multiple feeds, output is an ordered filtered stream, and failures are handled in a bounded way. It does not explain all parameter interactions or output schema, but an output schema exists to cover return structure. Given the moderate complexity, the description is nearly complete but lacks some parameter-level nuance.

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 0%, so the description must compensate. It mentions 'filtered' (mapping to keywords), 'deduplicated' (mapping to deduplicate_by), and 'time-ordered' (mapping to since_hours), which gives high-level meaning. However, it does not explain the distinction between limit and per_feed_limit, nor the exact behavior of since_hours null values. The description provides partial parameter semantics, enough to understand intent but not full parameter-level detail.

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 uses a specific verb 'Merge' and specifies the resource ('two to eight public RSS or Atom feeds'), the transformations ('filtered, deduplicated, time-ordered'), and the output ('news stream'). It clearly distinguishes from sibling tools like research.feed-normalize by focusing on aggregation of multiple feeds.

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 establishes clear context: use when merging 2-8 feeds into a single ordered stream. It does not explicitly name alternative tools or state when not to use it, but the explicit 'two to eight' range implies a single feed would be handled elsewhere. No exclusions are mentioned, so it gets a 4 rather than 5.

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