update_custom_entry

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It's a mutation operation (implied by 'update') but says nothing about whether fields are merged or fully replaced, whether id must exist, whether missing optional fields are preserved or cleared, or any permission requirements. Two-parameter tool with a complex nested data object warrants more disclosure.

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?

The description is extremely short (a single phrase), which is concise, but this is under-specification rather than efficient specification. There's room for more useful content without approaching verbosity - one or two sentences explaining update semantics and use case would be appropriate.

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?

This is a mutation tool with no annotations and no output schema. With a nested data object, partial-vs-full replacement ambiguity, and 50% schema coverage, the description is far too sparse to guide correct invocation. An agent needs to know update behavior, id semantics, and whether partial updates are supported - none of this is conveyed.

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 only 50% - two parameters (id, data) exist with only the id having description, and the data object's nested fields have descriptions but the 50% figure likely reflects the top-level. The description itself adds zero parameter information beyond what the schema provides, and doesn't explain the update semantics (e.g., partial vs full replacement of the data object).

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 'カスタムエントリを更新' (Update custom entry) states a verb+resource but is essentially a restatement of the tool name with no additional detail about what a custom entry is or how updating differs from related create/get/list operations. It doesn't distinguish from siblings like update_persona, update_career_entry, etc.

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?

No mention of when to use this tool versus alternatives. There are many update_X siblings, and without distinguishing context (e.g., what custom entries are used for, whether all fields are replaceable or partial), an agent can't decide when this applies versus other update tools or get_custom_entry.

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