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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description still adds genuine context beyond that: smart fields render as placeholder labels (not resolved data), it works without a recipient, and it renders the draft tree unless content="published" is passed. That is meaningful disclosure for a preview tool, though it says nothing about rendering cost or limits.

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 what the tool produces (placeholder HTML, no recipient) before the workflow guidance, and the parenthetical examples make the abstract claim concrete. It is dense and packed with em-dash clauses, slightly more than strictly needed, but no sentence is 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 values need not be enumerated, yet the description usefully points the agent at the `html` field and tells it what to look for (overlapping lines, spacing). Combined with the placeholder semantics, the draft/published switch, and the confirmed absence of a recipient requirement, nothing an agent needs to call this correctly 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 description coverage is 100%, so the schema already documents id, content, and context, including the draft default. The description only restates the default and glosses 'published' as 'the live copy', which adds little beyond the enum descriptions. Baseline 3 applies.

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 (render a signature to HTML) and immediately qualifies it with the distinguishing trait: PLACEHOLDER values, each smart field showing its label, and no recipient required. This lets an agent tell it apart from get_signature_html (real rendered output) 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?

Gives explicit workflow positioning: use it to verify layout/spacing after create_signature or update_signature and before publish_signature, and fix the draft if the result is wrong. The 'no recipient needed' clause implicitly scopes it against recipient-based rendering, but no alternative tool is named and no explicit when-not condition is stated, so it stops 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.