lookup

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

With no annotations provided, the description carries the burden and does disclose a genuine behavioral trait: it never raises for a missing key, signalling that callers should inspect a flag rather than catch exceptions. It also enumerates the returned fields, though the meaning of `found` is only implied rather than spelled out.

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 short clauses, purpose first and the behavioral caveat second, with no filler. Every element — verb, resource, return shape, missing-key behavior — 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?

For a one-parameter read tool with an output schema, the description covers what it does, what comes back, and the key edge case. Minor gaps remain around key formatting and whether lookups are scoped to any namespace, but nothing critical to a correct call 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 coverage is 0%, so the description must compensate for the single undocumented `key` parameter. Saying the value is stored 'under `key`' establishes that it is the lookup identifier, but gives no format, casing, namespace, or examples that would help an agent construct a valid key.

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?

A specific verb plus resource ('Read the value stored under `key`') that makes the read-only nature unambiguous, implicitly separating it from the write-side siblings `store` and `add`. It does not name those siblings explicitly, so it stops short of a 5.

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?

Usage is implied by 'Read the value stored under `key`' — an agent understands this is the retrieval path — but there is no explicit when-to-use versus `store`/`add`, nor any stated precondition. The only guidance is behavioral (missing keys do not raise), which is not a selection rule.

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