crm_update_contact

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

Adds significant detail beyond annotations: states it's a write operation, only passed properties are sent, previous values are lost, omitted properties are untouched, retries are safe, requires the write scope, invalidates cache, and raises specific errors. Consistent with annotations; no contradiction.

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?

The description is compact yet comprehensive, covering purpose, usage, behavior, scope, cache, and errors in a logical order without redundancy. Every sentence adds value.

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 6 parameters and an output schema, the description is complete. It addresses when to use, how it behaves, required permissions, error cases, and side effects. The output schema covers return details, so no need to elaborate on that.

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 descriptions already exist per parameter. The tool description adds general semantics about partial updates and overwrite behavior, which enriches understanding of how all parameters behave.

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 'Update properties on an existing HubSpot contact and return the updated record,' with a specific verb and resource. It also distinguishes from the sibling create tool, saying 'Use crm_create_contact for records that do not exist yet.'

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?

Explicitly says 'Use this to change a known record' and directs to crm_create_contact for new records. Error cases (unknown/archived id, no property supplied) provide additional context on when the tool is appropriate.

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