ga4_update_data_stream

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

Without annotations, the description carries the full burden. It discloses write behavior, immutability of stream type, and updateMask mechanics. However, it omits details about side effects (e.g., whether other fields are preserved) and the return value.

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 sentences plus prerequisites note. Extremely concise, front-loaded with the WRITE tag and core purpose. No redundant information.

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 5 parameters and no output schema, the description covers main behaviors and preconditions. It could hint at the response format or typical use cases, but overall it's fairly complete.

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 80%, so baseline is 3. Description adds value by explaining body for nested/advanced fields, updateMask derivation, and stream type immutability, which goes beyond schema descriptions.

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 it updates a data stream with an example (display name) and notes immutability of stream type. The GA4 WRITE tag reinforces the action. However, it does not differentiate among numerous ga4_update_* sibling tools.

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?

Provides clear guidance: pass only changed fields, updateMask derivation, and explicit updateMask for nested paths. Also specifies prerequisites (GA4_MCP_ENABLE_WRITES=true, confirm=true). Does not mention when to use alternatives.

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