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

Annotations already declare the safety profile (not read-only, not destructive, not idempotent, closed-world), so the bar is lower. The description adds genuinely useful behavioral detail beyond that: this is a patch-style operation where omitted fields retain their values, which an agent needs in order to construct a correct minimal payload.

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 sentences, both earning their place, with the core verb and resource front-loaded and the partial-update rule immediately following. No filler.

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 nested-object mutation tool with no output schema, the description says nothing about what the response returns (e.g., whether the updated tool object or a signing secret is echoed) or about failure modes like invalid URL rejection. The schema carries constraints, but return behavior is left entirely undocumented.

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% and the nested 'data' object documents each field (url, name, method, parameters, timeout_ms, description) with constraints. The description adds no parameter-level detail beyond the patch semantics, so baseline 3 is appropriate.

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 states a specific verb (update) applied to a specific resource (tool) and clarifies the partial-update model with 'Omitted fields retain their values.' It implicitly contrasts with create_tool/delete_tool/get_tool via the verb, though it never names a sibling 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?

Usage is implied by the verb and the partial-update semantics, which tells the agent it only needs to pass changed fields. However, there is no guidance on when to use this versus create_tool for a new tool, nor any prerequisites such as ownership or permissions.

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