Read a Marketing Cloud Next / Data 360 record

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

With no annotations provided, the description carries the full burden. It discloses the read-only nature (GET, kind 'read') and states the requirement for the path parameter, which are useful behavioral cues. However, it does not mention potential error responses, authentication needs, or rate limits, and it does not clarify whether the operation is safe or idempotent beyond the 'read' label. This is minimal but not misleading, so a score of 3 is appropriate.

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?

The description is a single, tightly written sentence that front-loads the core action and the critical requirement. There is zero wasted language, and every word contributes to clarity. It is an example of efficient specification.

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 operation with no output schema and no annotations, the description provides the bare essentials but omits context about response format, error handling, or when to prefer this over mcnext_query. It also does not explain that endpointId must be discovered via mcnext_list_endpoints, though that is covered in the schema. Given the simplicity of the tool, it is minimally adequate but could benefit from a sentence on usage context or typical workflow.

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 each parameter already has a description. The tool description adds value by explicitly stating 'Requires the path parameter,' which is not marked as required in the schema (only endpointId is). This clarifies a common usage pattern and helps the agent understand that pathParams is typically needed, even if not schema-required. This additional guidance warrants a 4 rather than the baseline 3.

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 states a specific verb ('Fetch'), a resource ('a single record'), and the method ('by id or key, GET'). This clearly distinguishes it from siblings like mcnext_query (which implies multiple records) and mutating tools like mcnext_create/update/delete. It also explicitly labels the operation as a read, leaving no ambiguity about its purpose.

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 description mentions 'Requires the path parameter' but does not explicitly state when to use this tool versus alternatives like mcnext_query. It implies use for single-record retrieval, but lacks explicit exclusions or conditions (e.g., 'for multiple records, use mcnext_query'). The schema does reference mcnext_list_endpoints for endpoint discovery, but that is outside the description, so the guidance is only implied, not explicit.

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