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

Annotations already declare destructiveHint=true and idempotentHint=false, so the safety profile is partially covered. The description adds useful behavioral meaning by explaining the resulting rule (a per-visitor message cap within a session window), but it does not clarify that this overwrites existing workspace settings, who may call it, or why it is flagged destructive despite being a settings update.

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 single sentence with no filler, front-loading the subject ('the workspace rule for proactive messages') before the parameter semantics. It is efficient, though the fragmentary phrasing slightly delays clarity about the action being performed.

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 two-parameter mutation tool with no output schema and no schema descriptions, the description adequately explains the parameters but leaves the action verb, the overwrite behavior, and sibling differentiation (update_frequency_cap) unaddressed. Adequate but with clear gaps.

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 0%, so the description carries the burden, and it does well: it explains that perSession is the number of new messages allowed and sessionMinutes is the length of the visitor visit window, giving meaning to both parameters beyond the bare min/max. It still omits units for sessionMinutes and the 0-10 ceiling on perSession, keeping it short of a 5.

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 identifies the resource ('the workspace rule for proactive messages') and even defines the rule's semantics, but it is written as a noun phrase rather than a verb+resource action, so the agent must infer that it sets/updates rather than reads it. It also fails to distinguish itself from a close sibling like update_frequency_cap, leaving the exact scope ambiguous.

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?

There is no when-to-use guidance, no prerequisites (e.g., admin permission, existing proactive message needing a cap), and no mention of the similarly named update_frequency_cap or update_proactive_message as alternatives or complements. The agent gets no routing help.

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