contacts_lookup_emailLook up an email address against Apple Contacts to find matching people entries. Returns zero or more ranked matches, helping identify who owns or uses the email.
Resolve one email address to matching Apple Contacts entries. Returns zero or more ranked matches.
| Name | Required | Description | Default |
|---|---|---|---|
| maxResults | No | ||
| emailAddress | Yes |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds meaningful context beyond the readOnlyHint annotation: it clarifies that it returns zero or more matches (not guaranteed a single result), and that results are ranked. However, it doesn't disclose ranking criteria, pagination behavior, or whether it performs fuzzy matching. For a read-only lookup, this is good but not complete.
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 concise sentences, front-loaded with the core operation and result behavior. No wasted words; every sentence earns its place.
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 no output schema, no annotation beyond readOnlyHint, and 0% schema coverage, the description is minimal but covers the essential purpose and return cardinality. It lacks details on ranking, maxResults, and error handling, but provides enough to invoke the tool correctly for a simple lookup 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 description coverage is 0%, so the description must compensate for undocumented parameters. It names the input implicitly ('email address') but doesn't explain the maxResults parameter at all. The baseline when schema coverage is low is 2, but the description adds minimal value by naming the input; however, it fails to compensate for the missing maxResults semantics.
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?
Specific verb ('Resolve') and resource ('email address to matching Apple Contacts entries'), clearly distinguishing it from siblings like contacts_lookup_phone and contacts_search_name. The scope is well-defined and immediately actionable.
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 description implies use when you have an email address and need to find contacts, but it doesn't explicitly state when to use this tool versus alternatives or what prerequisites might exist. Sibling tools are not mentioned, leaving the agent to infer selection based on input type.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.