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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety profile is covered. The description adds genuine context the annotations cannot: the required admission sequence (enroll then bind_actor) and the explicit mutation boundary ('You do not unlock doors'). It does not cover failure behavior if admission is missing, so it stops short of a 5.

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 short sentences with the admission prerequisite front-loaded as a bracketed callout, which is the right thing to put first. The 'enter / request access / return / exit' clause is a little padded but does describe view content rather than repeating the name.

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 carries the burden of describing what comes back, and it does so reasonably: rooms on the matter, OPEN vs LOCKED states, the reasons behind locks, and the available entry/exit paths. Prerequisites are stated. The reliance on 'hall'/'door' metaphor is the only real gap for an agent trying to map results to domain entities.

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% and both parameters (actor_token, matter_id) are fully documented in the schema, so the baseline is 3. The description adds nothing about parameter format, token lifecycle, or the single-matter default that isn't already in 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?

The sentence 'Lists every room on this matter, which doors are OPEN, which are LOCKED, and why' gives a concrete verb (lists) and resource (rooms plus their access states), which distinguishes it from action siblings like atlas.enter_room and atlas.request_room_access. The framing 'The hall, after admission' is atmospheric rather than informative, but the operational purpose is recoverable.

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 prerequisite chain is explicit ('NEEDS ADMISSION: enroll, then atlas.bind_actor'), and 'You choose among OPEN doors. You do not unlock doors' implies this is diagnostic rather than an access-granting action. However, no sibling is named as the follow-up for actually entering or requesting access, so the agent must infer from atlas.enter_room / atlas.request_room_access.

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