Update activity

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

Annotations already declare it as a non-read-only, non-idempotent, non-destructive open-world write, so the safety profile is covered. The description adds one genuine fact beyond the structured data: the upstream endpoint is undocumented and has no known body format, which tells the agent not to expect contract guarantees. It does not mention permissions, error behavior, or what happens to omitted fields.

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?

Two short sentences, the core action front-loaded, and the invocation hint placed second. Efficient and free of filler, though the framing about StreamElements documentation is slightly verbose.

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 mutation with no output schema and full schema coverage, the description is honest about the upstream documentation gap but leaves the agent without actionable knowledge of which fields can be changed, what authorization is needed, or how failures surface. It is adequate but visibly incomplete for a write operation.

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 coverage is 100%, so the baseline is 3. The description restates that fields-to-change go in `changes`, but `changes` is an unconstrained object (additionalProperties: {}), and the description does not enumerate any valid field names or value shapes, so it adds little beyond the schema.

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?

States a specific verb+resource ('Update an activity'), which is unambiguous against read-oriented siblings like activities_list, activities_get, and activities_replay. It does not explicitly name those siblings as alternatives, so it stops short of 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?

The only usage direction is the invocation mechanic 'pass the fields to change in `changes`.' There is no statement of when to use this tool versus activities_list/activities_get/activities_replay, no prerequisites or permission context, and no indication of what a valid update requires.

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