get_last_digest

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

With no annotations, the description carries the full burden and does well: it discloses that no regeneration occurs, that the call is instant and free, that results may be stale, and that generation time is in the response. It stops short of stating caching/auth behavior, but covers the key traits.

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?

Front-loads the core distinction ('without regenerating it') and adds only two short, high-value sentences with no filler.

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?

An output schema exists, so return-value details needn't be repeated, and the staleness caveat plus the generation-time pointer make the description sufficient for correct invocation. Minor gaps only.

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?

Zero parameters, so baseline is 4; there is nothing further the description needs to convey about inputs.

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?

States a specific verb ('Return') and resource ('most recently generated digest') and immediately differentiates from the sibling get_digest by specifying 'without regenerating it'. An agent can distinguish it from get_digest without opening either schema.

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?

Provides clear context for use ('Instant and free') and a condition for relying on the output ('check whether it is recent enough'). It doesn't explicitly name get_digest as the alternative for fresh digests, leaving that inference to the agent.

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