@striderlabs/mcp-american

modify_trip

Change flights on an existing American Airlines reservation. Initiates the flight change flow, allowing selection of new departure or return dates.

Instructions

Change flights on an existing American Airlines reservation. Initiates the flight change flow — use search_flights to find new options.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "recordLocator": "<recordLocator>"
    },
    "name": "modify_trip"
  }
}

Input Schema

Name	Required	Description
`lastName`	No	Passenger last name
`newReturnDate`	No	New return date in YYYY-MM-DD format (round trips)
`recordLocator`	Yes	The 6-character confirmation code (e.g., 'ABC123')
`newDepartureDate`	No	New departure date in YYYY-MM-DD format

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 3, 2026

TDQS

A3.8/5.0

Behavior3/5

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

With no annotations, the description carries the transparency burden. It discloses that the tool 'initiates the flight change flow,' indicating a multi-step process, but does not explain the full outcome, required permissions, or whether the change is immediately applied. This is some context but leaves significant ambiguity.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences, front-loaded with the main purpose and followed by a practical prerequisite. No wasted words; every part contributes to understanding.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Despite clear purpose and schema, the description omits information about the flow's next steps, what the tool returns (no output schema), and how the change is completed. Given the tool's complexity and lack of annotations, this is a notable gap for an agent to know what to expect.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, and each parameter has a description (e.g., recordLocator, newDepartureDate). The tool description adds no extra parameter nuance, but the schema already documents what each field means, so the baseline of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool changes flights on an existing American Airlines reservation, using a specific verb ('change') and resource ('existing reservation'). It distinguishes itself from sibling tools like cancel_trip and search_flights by focusing on modification.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear usage context by instructing to use search_flights to find new options before changing flights. It implies a workflow but does not explicitly state when not to use, such as for cancellations or check-ins, though sibling names make this inferable.

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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