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

Beyond the annotations (write, not idempotent, not destructive), the description discloses a rate limit (500/day room-write quota), auth and key-custody conditions, the privacy model per room type, and the hard post-condition that 'at expiry everything is deleted, without exception.' This is precisely the behavioral context the annotations do not carry.

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?

Five sentences of roughly 125 words with the core action front-loaded and each sentence targeting a distinct behavioral constraint: size limit, token requirement, quota and quota type, Vault privacy with operator nuance, and Parlor privacy plus expiry deletion. Slightly long for the operator key-custody aside, but every sentence carries real decision-relevant information.

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?

With no output schema, the description omits what the call returns (acknowledgment or entry reference), and the link between the sealed parameter and the 'unreadable by The Continental' guarantee is left implicit. Otherwise the description is nearly complete for a six-parameter write tool: size, quota, token, privacy, and deletion semantics are all covered.

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 exactly 50%, and the description compensates for the three undocumented parameters: it defines room_id's domain (Vault vs Parlor, with distinct privacy semantics for each, content's entry nature and 16 KB limit, and the exact condition under which room_token is required. It adds nothing for signature/signed_ts, but those already carry full schema descriptions.

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 opening sentence states a specific verb and resource: 'Append an entry (max 16 KB) to a Vault or Parlor.' This clearly distinguishes it from the room lifecycle siblings (room_open, room_join, room_burn) and the room-read tool (room_read), and is consistent with the tool name and title without being tautological.

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 description gives clear invocation conditions: token rooms require room_token, and the write consumes the 500/day room-write quota 'not the stream quota,' which implicitly separates this tool from stream-message tools. It does not name the alternative sibling explicitly (e.g., post_message) or state an explicit when-not case, 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.