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

With no annotations, the description carries the burden and does well: it discloses the mutation semantics (write/revise), the side effect (a preview_id is created), the session-scoped storage, and a hard content constraint. It leaves some gaps — it never says whether revising overwrites prior pages, whether previews expire, or what happens on failure.

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?

Four dense sentences, fully front-loaded: the core action first, then usage trigger, then the sibling alternative, then the hard constraint. Nothing is redundant padding.

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 4-param write tool with no output schema and no annotations, the description covers action, trigger, alternative, and key constraints, which is nearly enough. The remaining gap is error/overwrite behavior, which is not covered anywhere in the structured data.

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 baseline is 3 and the schema already explains title, content, update_preview_id, and notification_message. The description reinforces the create-vs-revise meaning of update_preview_id and the content rules, but adds no syntax or format detail beyond the schema.

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+resource+effect: 'Write or revise draft markdown into session storage (creates preview_id).' It explicitly distinguishes itself from the sibling pdf__get_preview ('For showing an existing draft use get_preview'), so an agent can route correctly 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 an explicit when-to-use trigger ('when the user asks to create/write/edit document content') and names the alternative for the opposite case (viewing an existing draft → get_preview). It also clarifies the audience constraint ('Agent-only — not a suggestion button'), removing an ambiguity an agent would otherwise have to guess at.

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