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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false. The description adds no additional behavioral context (no return shape, no note that the call is a no-op or deprecated). It only implies the underlying concept was removed, without clarifying what invoking it does.

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?

It is short, but the leading "Removed:" fragment is confusing and not front-loaded with a purpose statement. The sentence structure reads like a changelog note rather than tool documentation.

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 zero-parameter list tool with no output schema, the description should at least state what is returned or whether the tool is still callable. Instead it is a cryptic deprecation note that leaves an agent unsure whether to invoke it or defer to list_views.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. No parameter semantics are required or missing.

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 opens with "Removed:", a tombstone that never states what list_digests actually does or returns. It obliquely explains what a Digest is ("an email and a file") but gives no usable statement of purpose for this tool; an agent cannot tell what calling it would accomplish.

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 does route the agent elsewhere by naming list_views as the source of digest information ("list_views says which Views send one"), which is a usable alternative pointer. However, it never says when this tool itself should be used, so the guidance is partial and ambiguous.

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