update_contact

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

Discloses that the name is stored only locally, never sent to the contact, and overrides the contact's profile name in displays. Lacks mention of reversibility or persistence but is adequate for a simple update operation.

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?

Well-structured with purpose, effect, context, and exclusions. Though slightly verbose, every sentence adds value and the key information is front-loaded.

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?

Fully covers what the tool does, its local-only scope, its effect on displays, and provides alternatives. No output schema exists, so the description adequately fills all gaps.

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% with clear descriptions for both parameters. The description adds marginal value by explaining the purpose of the name parameter, but does not significantly enhance understanding 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?

Clearly states it sets or updates the local display name for a Signal contact. Specifies verb and resource, and explicitly distinguishes from sibling tools like update_profile, block_contact, and remove_contact.

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 explicit when-to-use (adding a human-readable label) and when-not-to-use (for changing own profile, blocking, or removing). Also suggests using list_contacts first.

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