ghl_contact_lookup

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

Annotations already declare the full safety profile (readOnlyHint, idempotentHint, destructiveHint=false), so the bar is lower. The description still adds useful behavior: matching against additional emails/phones, and returning an empty `contacts` array on no match. It does not cover rate limits, error behavior, or what fields a contact record contains.

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?

Core matching rules are front-loaded and the sentences are dense with signal. Minor waste in the trailing line 'Pagination params: limit — pass them to page through full result sets', which is redundant and grammatically muddled given `nextCursor` is the actual paging mechanism.

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 5-param read tool with no output schema, the description covers pagination, the empty-result case, auth channel, and scoping — enough to invoke it correctly. Missing only the return shape of a matched contact, which an agent may want before calling.

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 100%, so every parameter is already documented in the schema, including mutual exclusivity, E.164 format, and the 20-item cap. The description's parameter content largely restates that. Baseline 3 is appropriate.

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?

States a specific verb and resource ('Lookup Contact By Email Or Phone') and pins the matching semantics ('exact `email` or `phone`, scoped to a location'), so an agent knows this is a precise identity lookup. It never names the obvious alternative (ghl_contact_search_advanced) to confirm the boundary, which keeps it short of a 5.

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?

Gives real preconditions: 'Exactly one of `email` or `phone` must be provided' and 'OAuth channel only', plus how to page with `nextCursor`. It stops short of saying when to prefer this over the sibling search/list tools, leaving the main routing decision implicit.

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