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

With no annotations, the description carries the full burden. It does disclose a key behavioral trait: the tool produces only a count and discards titles. However, it does not describe data source behavior, freshness, network dependency, or error conditions, so transparency is only partial.

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 description is two short sentences with the action front-loaded and no filler. Every word adds value: the purpose is stated first, and the important behavioral caveat about titles is included.

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 simple, read-only count tool with no required parameters, the description is largely complete. It states the action and implies the return value is a count. However, the absence of annotations and an output schema, plus 9 optional parameters, leaves minor ambiguity about whether a caller should provide a feed or no parameters at all.

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 schema has 100% description coverage, so the baseline is 3. The description adds no additional parameter-level guidance beyond what the schema already provides. 'Titles discarded' mirrors the feed parameter description but does not clarify which of the 9 optional parameters should be supplied, if any.

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 states a precise verb and resource: 'Count current Hacker News front-page stories.' It also adds a clarifying boundary, 'Titles discarded,' which distinguishes this tool from fetch or retrieval tools that would return story content. This is specific enough to differentiate it from siblings like web-fetch or fetch-status.

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 intended use is implied clearly: use this tool when a count of current Hacker News front-page stories is needed. However, it does not explicitly mention alternatives, exclusions, or when not to use it, leaving some routing decisions to inference.

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