objects_update_custom_object

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

Annotations already indicate readOnlyHint=false, idempotentHint=true, and destructiveHint=false. The description adds no behavioral context beyond the verb 'update'. It doesn't disclose whether the operation is a partial or full replacement of the schema, what happens to existing fields, or any side effects. Since the description carries no additional behavioral insight beyond what the annotations already declare, it falls short.

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 a single short sentence, which is concise and free of fluff. However, it is under-specified and lacks any structural breakdown of the operation. While it doesn't waste words, it also doesn't provide enough substance to be considered well-structured. It's not a tautology, but it's on the border of being too terse for the complexity of the tool.

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 5 parameters and no output schema, this description is incomplete. It doesn't mention what the response will be, which fields are updatable, or any important preconditions (e.g., the key format, the need for a custom object prefix). The description gives only a one-liner and leaves the agent to infer most operational details from the schema and annotations. Given the complexity and the absence of an output schema, more context is needed.

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 100% description coverage, with all five parameters documented (key, labels, locationId, description, searchableProperties). The description itself doesn't add any parameter-specific meaning, but the baseline is 3 given high schema coverage. It doesn't contradict or enhance the schema, so a 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 clear action ('Update') and target ('Object Schema'), but the phrase 'By Key / Id' is misleading because the schema only includes a 'key' parameter, not an 'id'. It also doesn't explicitly say 'custom object' (only in the tool name), and doesn't distinguish from the sibling 'objects_update_object_record' which updates a record, not a schema. It's clear enough that it updates a schema, but the ambiguity around the identifier and the lack of explicit resource specificity prevent a higher score.

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 is given on when to use this tool versus alternatives. It doesn't mention that it's for modifying an existing custom object schema (as opposed to creating or getting one), nor does it exclude scenarios. The description provides no context about prerequisites or when this tool is the right choice among the many object-related siblings.

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