Track an inbound event that can trigger automations. Requires event name, messageId (for deduplication), and properties.
| Name | Required | Description | Default |
|---|---|---|---|
| event | Yes | The event name (appears as trigger in Automation Trigger node) | |
| userId | No | User ID associated with the event | |
| messageId | Yes | Unique ID for deduplication (returns 409 if not unique) | |
| properties | Yes | Event properties payload |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description adds meaningful behavioral context beyond the annotations by stating that tracking can trigger automations, which is a key side effect. It also highlights the deduplication role of messageId, complementing the idempotentHint annotation. No contradiction with annotations exists.
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 efficient sentence that front-loads the core purpose and then lists the required inputs. Every word earns its place; no filler or repetition of schema details.
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 4-parameter tool with a 100% covered schema and clear annotations, the description sufficiently covers what the tool does, what it requires, and its side effects. It does not describe response output, but no output schema exists and the core invocation context is complete.
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 schema already documents all four parameters. The description restates the required parameters and adds little beyond the schema, aside from emphasizing messageId for deduplication, which the schema already mentions. Baseline 3 is appropriate.
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 uses a specific verb ('Track') and resource ('inbound event') and states the purpose ('can trigger automations'). It clearly distinguishes this from sibling invoke_* tools by emphasizing inbound event ingestion rather than direct invocation.
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 phrase 'Track an inbound event' establishes clear context for external event ingestion, and 'that can trigger automations' signals its relationship to automation tools. It does not explicitly name alternatives or exclusions, but the context is clear enough for an agent to select this over invoke_automation_template or invoke_ad_hoc_automation.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Tools are mostly organized as distinct resource/action pairs, but several clusters are easy to confuse: list subscription tools (add_subscribers_to_list vs bulk_subscribe_to_list vs subscribe_user_to_list), message vs message-content vs message-history retrieval, and the many journey/journey-template list/get tools. Detailed descriptions rescue most selections, but the sheer number of near-identical verb/resource names creates real misselection risk.
Almost all tools follow a snake_case verb_noun pattern (create_, get_, list_, replace_, send_, publish_, archive_). Minor deviations keep it from a perfect score: courier_installation_guide is noun-first, and add_bulk_users sits awkwardly next to the bulk_add_* family, but the overall convention is predictable and readable.
144 tools is an extreme working-set size for an agent to hold and choose from, far beyond the reasonable 3–15 range. Even for a broad platform like Courier, this should be split into focused sub-servers (templates, journeys, users, lists, preferences, etc.) to remain usable.
The surface is remarkably comprehensive, covering sending, templates, journeys, automations, users, tenants, lists, preferences, providers, routing, brands, audiences, translations, digests, bulk jobs, and audit events. Notable gaps exist—automation template CRUD and digest schedule management are missing—but most workflows can still be completed with workarounds.
