update_todo

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

With no annotations, the description carries the behavioral burden. It clarifies that the tool accepts plain fields and RFC 5545 properties without iCal formatting, which is useful. However, it does not mention effects such as whether fields are replaced, how partial updates behave, or any conflict/error behavior, though the etag schema does cover conflict detection.

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?

A single sentence front-loads the key differentiator ('PREFERRED' and 'without iCal formatting') and then compresses the supported field list efficiently. There is no filler or repetition of schema boilerplate.

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 3-parameter tool with nested fields and no output schema, the description covers the supported properties, formats, and scope well. It could more explicitly direct agents to update_todo_raw for raw formatting and describe the response, but the schema covers parameter details and the description is otherwise sufficient.

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 schema already documents all parameters with 100% coverage, so the baseline is 3. The description adds value by giving human-readable aliases (SUMMARY = title, DESCRIPTION = details), listing valid STATUS values, priority range, and explicitly noting support for custom X-* properties, which goes beyond basic schema text.

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 a specific verb and resource ('Update todo fields') plus a clear scope flag ('without iCal formatting'). It lists the supported properties and explicitly contrasts with the raw sibling, making it easy for an agent to distinguish update_todo from update_todo_raw.

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 'PREFERRED' marker and 'without iCal formatting' give clear context that this is the high-level update path and imply that update_todo_raw is for raw iCal formatting. It does not explicitly name the alternative or state when to choose raw, so it falls just short of a 5.

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