find_contact

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description does not contradict them. It adds genuinely useful matching semantics beyond the annotations: results are the 'closest matches' by 'case-insensitive substring', telling the agent to expect fuzzy, ranked, possibly multiple results rather than an exact lookup.

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?

Three short sentences: what it does, how matching works, when to use it. Each sentence earns its place and the core purpose 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?

For a simple 2-parameter read tool with a fully documented schema and safety annotations, the description covers purpose, matching behavior, and the calling context. It stops short of saying whether returned handles are directly usable for send_imessage or what happens when no match is found, but no output schema exists to fill that gap.

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% and both parameters are already documented there, so the baseline is 3. The description restates that the query spans name/phone/email as a substring, roughly duplicating the schema rather than adding new syntax or format guidance, and says nothing about the limit parameter.

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 states a specific verb and resource ('Search the user's contacts') and names the searchable fields (display name, phone, email), which tells an agent exactly what the tool retrieves. It does not explicitly distinguish itself from the sibling list_contacts, so the boundary between searching and listing is left implicit.

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 final sentence gives a concrete trigger ('when the user references someone by name to resolve them to a sendable phone/email handle'), which is clear actionable context. It omits when NOT to use it — most notably browsing the whole contact list via list_contacts — so the alternative routing is only implied.

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