Customers List Accessible Customers

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

Annotations already declare readOnlyHint=true, so safety is covered by structured data. The description still adds genuine behavioral context by clarifying that results are scoped to the authenticated caller's direct access, which matters for interpreting the returned IDs. It says nothing about pagination or result ordering, so it is not exhaustive.

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, no filler, and the primary guidance ('use this tool first') is front-loaded in the second sentence before the reason. Every sentence earns its place.

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 zero-parameter discovery tool with an output schema already covering the return shape, the description supplies everything needed: what it returns, its auth scope, and its role as the entry point before other customer-ID-dependent tools. Nothing required for correct invocation is missing.

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?

The tool takes zero parameters, which is the baseline-4 case; there is no parameter behavior left to explain. The description correctly implies the call is fully parameterless and derived from the caller's auth context.

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 names a specific verb and resource (returns IDs of accessible customers) and adds the scoping constraint that access is limited to the authenticating user. It does not explicitly name or contrast the siblings (metadata_get_resource_metadata, search_search), so it is clear but not fully differentiated.

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?

It states exactly when to reach for this tool: 'Use this tool first to discover available customer IDs if the user hasn't provided one,' plus the rationale that most other tools need a valid customer ID. The sequencing and trigger condition are unambiguous.

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