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

Annotations already declare readOnly/non-destructive/openWorld, and the description adds useful context beyond them: the returned payload (contacts, service location, last serviced date) and the auth requirement (Cotlet API key with access to this app). It doesn't mention pagination behavior, but the added value is real.

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?

Front-loaded and reasonably tight, but 'with last serviced date' appears twice in the first two sentences, which is genuinely redundant. The trailing auth sentence is useful but the overall prose could be trimmed.

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 read-only filtered-list tool with no output schema, the description covers what is returned, how it's intended to be used downstream, and the auth prerequisite. Sufficient for correct invocation, though pagination expectations are unaddressed.

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 params (page, tags, query) are already fully documented. The description reinforces the searchable fields (name, phone, email, address, tag) but adds no syntax or format detail beyond the schema, so the baseline 3 applies.

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 (list) and resource (customers) with the exact matching fields (name, phone, email, address, tag). An agent can distinguish this from service-fusion_create_customer and the get/list siblings immediately.

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 tells the agent to 'use it before create_customer to find a repeat caller by phone or email' and notes that create_job/create_estimate consume the returned name verbatim. Clear context, though it doesn't state when NOT to use it (e.g., direct lookup by ID).

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