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

Adds substantial context beyond the annotations: patch merge semantics (omitted fields unchanged, null clears only the named field), tier gating for passcode/expiry, and a security model for passcode entry. Consistent with destructiveHint=true (null clears fields) and idempotentHint=true (repeatable patch).

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-loaded with the core patch semantics and scope exclusions, then the security guidance. Most sentences earn their place, though the passcode-security block repeats the 'host receives it' point across the embedded-entry and app-only sentences.

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?

No output schema or annotation covers the safety/security dimension, so the description rightfully supplies patch semantics, tier limits, and passcode handling. It leaves captureFields behavior undocumented, which is the main gap for a 0%-coverage nested schema.

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 0% and the patch object is nested, so the description must carry the load. It explains the omit/null semantics that govern every field and details passcode and expiry behavior, but never mentions captureFields (name/email/phone) or what its enum values or null mean.

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 ('Patch reader settings only') and immediately distinguishes itself from siblings by exclusion ('Does not publish or change sharing recipients'), routing the agent away from publish_document and set_document_sharing. The read counterpart get_document_reader_settings is implicitly differentiated by 'Patch'.

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?

Clear when-not guidance (no publishing, no sharing-recipient changes) and explicit prerequisites for passcode/expiry mutations (Plus required, downgrade rules). However, it never names the sibling tools to use instead when it declines those operations, so routing is left to inference.

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