set_custom_property

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

No annotations are provided, so the description must disclose behavioral traits. It only states 'Set (upsert)', implying mutation, but does not specify whether it replaces or merges, if it is destructive, or if special permissions are required. The lack of detail leaves significant behavioral ambiguity.

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 very concise: one sentence plus a terse parameter list. It is front-loaded with the purpose. Every word serves a purpose, though the format could be more readable. It earns a 4 for efficiency.

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?

Given the tool's simplicity (three parameters, an output schema exists), the description is minimally adequate but lacks context about return values, default behavior for vt_type, or error conditions. The output schema likely provides return structure, but the description does not hint at it. For a simple upsert, a 3 is appropriate.

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 input schema has 0% description coverage, so the description must compensate. It explains vt_type as a 'VT type element name' with examples (lpwstr, i4, bool), adding meaning beyond the schema. However, it provides no extra context for name and value, leaving them as generic strings. This partial compensation warrants a 3.

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 uses the verb 'set' and resource 'custom document property', clearly indicating the action. It distinguishes from sibling tools like delete_custom_property and get_custom_properties. However, it does not elaborate on what a custom property is or the scope of 'upsert', which keeps it from a 5.

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 guidance on when to use this tool versus alternatives such as set_properties or other set_* tools. There is no mention of prerequisites, context, or when not to use it. The agent receives no help in deciding among siblings.

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