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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuinely non-obvious context: only supplied fields are sent, and the change propagates to the contact's guest records everywhere — useful scope disclosure for a destructive mutation. Missing auth/rate-limit or reversal info keeps it at 4.

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?

Two compact sentences, front-loaded with the WRITE marker and ending with the endpoint path. No filler; each clause carries meaning.

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 4-parameter mutation with no output schema, the description supplies the essentials: partial-update semantics, blast radius across guest records, and the underlying endpoint. It omits edge-case behavior (clearing a field, email uniqueness conflicts), which prevents a 5.

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 50% and the description restates the three optional attributes already declared in the schema without adding format or constraint detail. The valuable parameter documentation (contact_id formats, the {name,value} field pairs) lives in the schema, not the description, so baseline 3 applies.

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 ('change') and resource (a contact) and enumerates the mutable attributes: email, company, fields. The 'WRITE:' prefix and 'change' clearly separate it from the sibling read tools and from evenium_create_contact, though no sibling is named explicitly.

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?

'Only what you pass is sent' establishes partial-update semantics, which implies when this is appropriate versus a full replacement. However, it gives no explicit when-to-use/when-not guidance relative to evenium_create_contact or evenium_update_guest_status.

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