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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description adds genuine behavioral context the annotations don't: the default resolution to the newest digest when id is omitted. It does not cover error behavior (e.g., unknown id), keeping it from a 5.

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 short sentences, front-loaded with the primary retrieval behavior and followed by the default and usage hint. Every sentence carries information; no filler or redundancy.

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 values need not be described. The description covers both parameters' effects including the no-arg default, which is the main ambiguity for a two-optional-param getter. Minor gap: no mention of what happens with an invalid id.

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 baseline is 3. The description goes beyond the schema by specifying the semantics of omitting both parameters (falls back to newest digest) and by tying type to a concrete value (daily_digest), adding meaning the schema property descriptions alone do not.

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 and resource ('Gets one digest by id or slug') plus the no-argument behavior ('newest digest when no id is given'), which cleanly separates it from list_digests. An agent can tell it retrieves a single record rather than a collection without reading the 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?

Gives an explicit trigger ('Use it when the user asks for the latest brief') and a parameter-selection hint ('Pass type daily_digest for the newest daily digest'). It lacks stated when-not-to-use conditions or a named alternative (e.g., list_digests), so it falls short of a 5.

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