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

readOnlyHint=true already tells the agent this is a safe read, so the description's main marginal contribution is the scoping context that results are link-attributed customers, plus the GET endpoint reference. It says nothing about pagination behavior, result ordering, or how multiple filters combine, so it adds only modest value beyond the annotation.

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 short sentences, the purpose and filter keys front-loaded. The trailing 'Dub: GET /customers.' is minor metadata but cheap and harmless; there is no padding or repetition.

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 parameterless-required list endpoint with no output schema, an agent still lacks return-shape and pagination expectations (page/pageSize exist in schema but the description never mentions paged results). What is present is accurate and sufficient to invoke the tool, but not sufficient to predict its response.

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%, with every one of the six parameters documented inline, so the baseline is 3. The description echoes three of the filter keys already described in the schema and adds no semantics (e.g., AND/OR behavior between filters) beyond what structured data provides.

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), and clarifies that these are customers Dub has attributed to links, which goes beyond a tautological restatement of the name. It also names the filter keys (email, external id, link), letting an agent distinguish it from the singular dub_get_customer without opening the schema. It stops short of explicitly contrasting itself with that sibling.

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 mention of filtering 'by email, external id or link' implies when this tool is useful (bulk retrieval or lookup by identifier) but never states when-not to use it or names dub_get_customer as the single-record alternative. Usage is inferable but not spelled out.

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