Lookup a cached plan

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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint, but the description adds valuable behavior beyond those: it specifies the return contents ('found, similarity score, and plan'), the default similarity threshold (0.68), and the auth requirement ('tool policy gate'). No contradiction with annotations.

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?

Five short sentences, each carrying distinct information: purpose, positive usage, exclusions, read-only nature, return shape, threshold, and auth. No filler; the most important behavior is front-loaded.

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 single-parameter read-only lookup tool with a rich output schema, the description covers the essential operational context: when to use, what it returns, the default threshold, and auth. Nothing an agent needs to invoke it correctly is missing.

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 the baseline is 3. The description only restates that the lookup is keyed by task_description, which the schema already says. It does not add new parameter-level detail such as length limits, example formats, or accepted wording.

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 specific verb ('Semantic lookup'), a resource ('a previously stored plan template'), and the key mechanism ('keyed by task_description'). It clearly distinguishes this from memory_read and plan_cache_put by naming them, so the agent can tell the tools apart immediately.

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?

Explicit usage guidance is provided: 'Use to reuse a multi-step plan' and 'Do not use to recall facts from memory (memory_read) or to write a plan (plan_cache_put).' This names both when to use and when not to use, with direct sibling references.

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