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

Annotations already declare readOnly=false, destructive=true, idempotent=false, and openWorld=true, covering the safety profile. The description adds the 'max 3 pinned' constraint and the mute_duration linkage, but does not explain why actions like archive/pin carry destructiveHint, whether they are reversible, or what permissions are needed.

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?

A front-loaded one-sentence summary followed by a scannable action table; every line maps to a real enum value. The action list partly duplicates the schema enum, but the human-readable glosses justify the space.

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 an output schema present, return values need not be described, and the action list plus annotations cover the operational essentials for a ten-action mutation tool. Remaining gaps are sibling routing and error/permission behavior, which are minor given the structured data available.

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 the enum for action already lists every value, so the schema does the heavy lifting. The description restates the same action set and repeats constraints already in the schema ('requires text', mute_duration usage, default 'forever') without adding format or validation detail.

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 ('Manage') and resource ('chat state') and enumerates all ten sub-actions with one-line semantics, so an agent knows exactly what the tool covers. It separates itself from the manage_labels/manage_notes/manage_reminders siblings via the 'chat' resource, though the distinction is implicit rather than called out.

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 action list tells the agent which action to pick for a desired state change, which is implied usage guidance, and it notes the mute_duration dependency and that set_draft requires text. It never states when this tool is preferable to a sibling or when an action should be avoided, so routing remains inferred.

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