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

Beyond the annotations (readOnly=false, idempotent=true, destructive=false), the description reveals the key behavioral trait: omitted fields are cleared, not kept. This is exactly the kind of side-effect disclosure that prevents an agent from assuming merge semantics.

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 with no filler. The warning about omitted fields is front-loaded right after the action statement, making the most important usage caveat immediately visible.

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 no output schema, the description covers the essential invocation caveat and the full-replacement semantics. It does not describe return values, but that is not critical for correct use, and the schema plus annotations handle required fields and idempotence.

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 description adds the critical whole-object semantic and explains that optional fields are not truly optional-preserving: omitting them clears them. However, schema description coverage is only 29% and the description does not clarify meaning of parameters like operator or scroll_depth, so it only partially compensates for the low coverage.

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: 'Replace a goal's definition.' This is sharper than the tool name 'update goal' and clearly differentiates the operation from patch-style edits, while the resource 'goal' distinguishes it from sibling update_funnel/update_site.

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?

It gives a direct usage rule: send the whole goal, and explicitly warns against sending only changed fields. It does not name alternatives or state when to prefer create_goal, but the guidance is concrete enough for an agent to call it correctly.

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