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

Goes well beyond the annotations by disclosing dedup rules (rows matching an existing phone or email are skipped), a validation rule (rows without a first name are skipped), that existing customers are never modified, that nobody is contacted, that the result reports counts of each skip type, and that it executes immediately. This is exactly the side-effect profile an agent needs for a mutation tool.

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?

Six short sentences, front-loaded with what the tool does and the batch limit, then progressive detail on dedup, immutability, and side effects. Every sentence carries distinct information with no repetition of the schema.

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 write tool with an output schema already present, the description covers the essentials: what gets written, what gets skipped and why, what is left untouched, and that no one is contacted. An agent can call this correctly without further inference.

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% at the top level, so the description must carry the load, and it does: it explains the 200-row cap, the required first name, and that phone/email drive duplicate detection. It stops short of describing the remaining item fields (notes, address, lastName) beyond what the schema itself implies.

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 ('Adds customers to the connected Nexwin account'), quantifies scope ('up to 200 in one call'), and names the source ('a list the user has pasted or uploaded'). No sibling tool does bulk customer import, and the description makes that role obvious against lookups like find_customer.

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 usage context is clear - bulk onboarding of a pasted/uploaded list - which implicitly routes the agent away from single-customer tools. However, it never names an alternative (e.g. find_customer for lookup) or states when not to use this tool, so the guidance is contextual rather than explicit.

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