read_cached_result

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

readOnlyHint already declares the safe read profile, so the description's value-add is pagination behavior: offset/length paging and the next_offset + remaining_chars continuation signal. That is genuinely useful behavioral context beyond the annotation, though it doesn't cover e.g. cache expiry or error 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?

Two tight sentences with no waste; the core purpose is front-loaded and the paging mechanics follow immediately. Every clause earns its place.

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?

There is no output schema, but the description compensates by describing the continuation fields (next_offset, remaining_chars) that tell the agent when paging is done. Remaining gaps like cache lifetime or slice size limits are minor.

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 coverage is 100%, so cache_id, offset, and length are already documented with defaults. The description only restates that offset/length drive paging, adding little semantic detail beyond the schema, so the 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?

"Read a slice of a large cached result produced by another tool" gives a specific verb (read), resource (cached result), and scope (a slice). It clearly distinguishes itself from list_cached_results by being about reading content rather than enumerating cached items.

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 states the trigger condition precisely (look for "cached":true + a cache_id in another tool's output) and explains the paging loop. It doesn't explicitly contrast against list_cached_results or say when-not to use it, but the context for invocation is clear.

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