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

Annotations already cover the read-only, non-destructive, idempotent behavior, so the bar is lower. The description adds only the vague 'history and provenance' notion, but does not disclose what the returned history contains, how far back it goes, or how versions are represented.

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?

The description is a single compact, front-loaded sentence with no filler. It is concise, though the brevity comes at the cost of parameter and usage detail.

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 tool with two parameters and no output schema, the description is too thin. It omits parameter semantics, return format, and any guidance distinguishing it from related email draft tools, so an agent may not call it correctly without external inference.

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 0%, and the description provides no parameter guidance. It does not clarify whether 'id' is a draft identifier or candidate identifier, nor what the optional 'request_id' means or how it affects results.

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 action ('Read') and resource ('candidate email draft history and provenance'), making the tool's general purpose clear. It does not explicitly differentiate itself from sibling tools like yardstick_email_drafts_read or yardstick_email_drafts_list, but the 'history' scope is enough to distinguish it at a basic level.

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?

The word 'history' implies when this tool is appropriate: when an agent needs historical versions or provenance rather than the current draft. However, the description does not explicitly name alternatives or state when not to use this tool, leaving the routing decision mostly to inference.

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