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

Annotations already declare destructiveHint=true, idempotentHint=true and openWorldHint=true, so the safety profile is covered elsewhere. The description adds nothing beyond them: no note on whether omitted fields are preserved, whether the update is partial or full replacement, or what happens to existing values.

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 short, front-loaded sentence with zero filler. It is efficient, but its brevity stems from under-specification rather than disciplined editing.

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 need no explanation, and annotations cover safety. What is missing is the essential input knowledge: which user fields may be passed in the free-form `input` object. For a destructive mutation tool with an untyped nested parameter, this is a significant gap.

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%, so the baseline is 3; 'by ID' merely restates the userId schema description ('Item ID'). Critically, the `input` parameter is a free-form object with additionalProperties {} and only 'Fields to update' as documentation, so the description does not compensate for the schema's silence on which user fields are valid.

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 ('Update an existing user') and scopes it to a single item via ID, which distinguishes it from glpi_create_user and glpi_get_user. It does not, however, say anything about what kinds of fields are updatable, which is the natural differentiator from sibling update tools.

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: nothing about needing a pre-existing userId (e.g., from glpi_get_user or glpi_search_user_by_email), no mention of prerequisites or permissions, and no comparison against alternatives. An agent must infer the whole workflow.

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