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

Annotations only declare destructiveHint=true; the description adds real behavioral context beyond that by emphasizing the operation MODIFIES live data and by disclosing partial-update semantics (omitted fields are left unchanged), which is critical to avoid accidentally wiping component settings. It also states the return value, useful since there is no output schema. Auth requirements and side effects on the public status page are not covered.

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?

Three terse sentences, front-loaded with the verb and the mutation warning, then usage, then transport/return details. No padding; every clause carries information an agent needs.

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 9-parameter mutation tool with 100% schema coverage and a destructiveHint annotation, the description supplies mutation severity, partial-update behavior, endpoint, and return value. Remaining gaps (auth/permission requirements, status enum semantics for each value) are minor, and the enum is fully enumerated in the schema.

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 meaningful semantics not present in the schema: the partial-update contract ('send only the fields you want to change') and a framing of status as the primary field to set. Listing the status enum values duplicates the schema's enum, but on balance this is slightly above baseline.

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 and resource ('UPDATES a component by id') and immediately scopes it as modifying live status-page data, which cleanly separates it from instatus_get_component and instatus_list_components. It even names the underlying endpoint, so the agent knows exactly which operation this maps to.

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 clear context for use ('The key way to set a component's operational status') and the partial-update rule 'Send only the fields you want to change', which tells the agent how to invoke it safely. It does not, however, name an alternative or state explicit when-not-to-use conditions relative to siblings like instatus_update_incident or instatus_create_maintenance.

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