STEP 2 of contact upload. Inserts contacts into Xmagnet using the field_mappings confirmed from preview_upload_mapping. Each contact must include the original column names as keys. Requires email per row. Max 500 per call. NEVER call before preview_upload_mapping.
| Name | Required | Description | Default |
|---|---|---|---|
| contacts | Yes | Rows as objects keyed by the ORIGINAL column headers | |
| field_mappings | Yes | {original_column: db_field} from preview_upload_mapping |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate readOnlyHint=false and destructiveHint=false, so the write nature is known. The description adds valuable behavioral context: 'Requires email per row', 'Max 500 per call', and the hard precondition about preview_upload_mapping. These constraints are not present in the annotations, and there is no contradiction.
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 extremely concise: four short sentences, each earning its place. It front-loads the step position ('STEP 2'), then explains the action, then states critical requirements. There is no fluff or redundancy.
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?
Given the tool's moderate complexity (multi-step upload, nested array parameter) and lack of an output schema, the description covers the essential context: purpose, step dependency, key requirements, and limits. It does not describe the return value or error behavior, which would improve completeness, but it is sufficient for basic correct usage.
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%, so the baseline is 3. The description adds operational semantics beyond the schema: it reinforces that contacts must use original column names as keys, and introduces new constraints ('Requires email per row', 'Max 500 per call') that are not in the schema. This adds meaningful value for correct invocation.
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 clearly states the tool's function: 'Inserts contacts into Xmagnet using the field_mappings confirmed from preview_upload_mapping.' It explicitly labels itself as 'STEP 2 of contact upload', distinguishing it from sibling tools like preview_upload_mapping and add_contacts. The verb 'inserts' and resource 'contacts into Xmagnet' are specific and unambiguous.
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 provides a strong usage guideline with 'NEVER call before preview_upload_mapping' and positions itself as 'STEP 2'. It doesn't explicitly discuss alternatives (e.g., when to use add_contacts instead), but the step context and the explicit precondition give clear situational guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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