cached_fetch

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

Fully describes behavior: cache lookup, instant return on hit, cache miss string, and cross-session caching. Since no annotations are provided, the description carries the full burden and meets it.

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?

Three sentences, front-loaded with purpose, each sentence adds value without redundancy. Fits the required structure.

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?

Complete for a simple lookup tool: explains input, output, and fallback workflow. No output schema needed as return values are textual and explained.

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?

Adds meaning beyond schema by explaining that url and prompt form a cache key and that prompt is an instruction for WebFetch. Schema coverage is 100%, but description enriches semantics.

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?

Description clearly states it looks up a URL+prompt pair in a local cache, returning cached output or a cache miss message. This distinguishes it from sibling tools like cache_list, cache_stats, and cache_store.

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?

Describes when to use (check cache) and provides a workflow on cache miss (call WebFetch then cache_store). However, it doesn't explicitly state when not to use or compare directly to siblings.

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