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

Annotations already indicate non-read-only (readOnlyHint=false), non-destructive (destructiveHint=false), and idempotent (idempotentHint=true). The description adds meaningful behavioral context: 'Only provided fields are changed' clarifies the idempotent partial-update behavior, and 'live Trident document' plus the token requirement provide additional context beyond the annotations.

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?

Three concise sentences with no fluff. The main action is front-loaded, followed by partial-update semantics and a practical prerequisite. Every sentence earns its place, and the description is appropriately sized for the tool's complexity.

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?

The tool has 6 parameters, a nested object, no output schema, and moderate complexity. The description covers the core action, partial update behavior, prerequisite for obtaining container IDs, and auth requirement. It does not explain error handling or return values, but given the idempotent and non-destructive annotations, it is reasonably complete. A 4 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?

Schema description coverage is 83% (baseline 3), and the description adds important meaning to the 'changes' parameter by stating 'Only provided fields are changed.' This directly clarifies the semantics of the nested changes object, which lacks a schema description. It also references containerId via the prerequisite, adding context.

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 clearly states the tool 'Updates properties of an existing container in a live Trident document', which is a specific verb+resource combination. It distinguishes itself from sibling tools like update_node and update_annotation by explicitly targeting containers, and additionally clarifies the partial-update semantics with 'Only provided fields are changed.'

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?

The description gives a clear prerequisite: 'Use get_document_summary to get all container IDs before calling this.' It also requires a valid editor access token. However, it does not explicitly state when to use this tool over alternatives (e.g., update_node for nodes), so it lacks full 'when-not-to-use' guidance.

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