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

Annotations already declare readOnly=false and destructive=false; the description adds the important partial-update rule and the fact that an empty string clears a field, which is real behavioral context an agent needs. It does not cover permissions, validation failures, or idempotency, so it is not exhaustive.

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?

Front-loads the core action, then patch semantics, then the field catalogue. The field list is a dense run-on, but every token is load-bearing for a nested object that the schema does not document.

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 mutation tool with one nested parameter, no output schema and no annotations on permissions, the description covers action, patch semantics, and field formats well. It omits what happens on invalid input or partial failure, which would complete the picture.

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?

The single schema parameter only says 'The fields to change, see the description', so the description carries the full burden: it enumerates all updatable fields and gives formats (two-letter country code, phone_type enum values, work_auth object shape, sponsorship list, numeric salary). This is substantially more than the schema provides.

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 ('application details'), making it distinguishable from get_application_details and update_profile at a glance. It does not explicitly name those siblings, so it stops short of the top tier.

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?

Explains partial-update semantics ('Only the fields given change; an empty string clears a field') and adds a genuine usage constraint ('Only values the person actually stated'). However, it never says when to reach for this over update_profile or get_application_details, so routing is left to inference.

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