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

Goes well beyond the annotations (readOnlyHint=false, idempotentHint=true, destructiveHint=false) by disclosing the permission model, the 50-pin-per-room quota, the idempotent re-pin behavior returning created: false, the 200-character note cap, that notes are untrusted text, and that pins surface in the handoff brief. These are exactly the behavioral facts an agent cannot infer from structured fields.

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 action and resource, then layered with constraints. Dense but nearly every clause earns its place; the trailing sentences on the handoff brief and untrusted notes are slightly tacked-on rather than integrated, which keeps it from a 5.

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 mutation tool with an output schema present, the description covers permissions, quotas, idempotency, and side effects (handoff brief visibility) without needing to explain return values. Nothing an agent needs to call this 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, but the description adds genuine meaning: message_seq and task_id are alternatives ('one ... or one ...'), and note is characterized as untrusted free text with a length cap. agent_id and room_id semantics are left to 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 (pin) plus the exact resources it targets (one room message via message_seq or one room task via task_id) and the effect ('as context for everyone in the room'). This clearly separates it from siblings like city_room_unpin, city_room_pins, and city_room_post.

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 real usage conditions: the host and members may pin while read-only guests cannot, and the pin lands in the handoff brief for new AIs. It also points at city_room_read as the source of message_seq. It does not name the complementary tool (city_room_unpin) for removal, so it stops just short of full routing guidance.

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