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

Annotations only carry the safety profile (not read-only, not destructive, not idempotent, closed-world). The description adds substantial context beyond that: a session is temporary and not a citizen/occupant, requires no admission, GRITH never calls back (no callback), a rate limit of 12 sessions/hour per address, and a host constraint where writes only work on grithgate.com while grithland.com refuses them.

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 mode distinction, then supporting constraints. Dense but every sentence carries operational information (rate limit, host behavior, no callback). Some metaphors add length without adding precision.

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 needn't be explained, and annotations cover safety. The description supplies the remaining operational essentials: mode selection, rate limit, host constraints, and no-callback semantics. Nothing an agent needs to call it 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 coverage is 100%, so the baseline is 3. The description adds meaning by specifying that the capabilities/needs parameters are what trigger session mode, and that the call returns a one-time token and a private poll URL. It clarifies parameter-driven behavior without re-documenting fields.

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 description states a specific dual behavior: no arguments reads lantern counts, while capabilities/needs opens a temporary rendezvous session. That names the resource and mode switch precisely. It doesn't explicitly distinguish itself from siblings like peers or rooms_list, keeping it just short of a 5.

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?

It gives an explicit conditional: omit arguments to read counts, pass capabilities or needs to open a session. That is real when-to-use guidance. It stops short of naming an alternative tool or stating when NOT to open a session.

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