421 Instructions 98648468

ATaC MCP Server Instructions

ATaC (Agentic Trajectory as Code) MCP Server provides tools to programmatically author, inspect, and execute trajectory workspaces (stored as .atac/<name>/index.yaml). Trajectories codify agent actions, conditions, and loops into reusable DSL assets.

Workflow for LLMs

When interacting with the ATaC MCP Server, follow this general workflow:

1. Initialize: Use atac_init to create a new, empty trajectory workspace.
2. Define State: Use atac_add_input to define required runtime parameters.
3. Build Logic:
   • Add tool calls using atac_add_action.
   • Add loops using atac_add_for.
   • Add conditional branches using atac_add_if.
   • Update state using atac_add_set.
4. Targeting (at parameter): All step addition tools support an at parameter to specify where the step should be inserted.
   • None (default): Appends to the root level.
   • 0: Inserts inside the body of step index 0 (e.g., inside a loop).
   • 0.then or 0.else: Inserts into conditional branches of an if step.
5. Inspect: Use atac_show to see the current structure and indices to calculate your next at path.
6. Execute: Use atac_run to execute the trajectory with specific inputs.

Available Tools

• atac_init(name: str, description: str) Creates the base workspace. Example: atac_init("search_task", "Find data")

• atac_add_input(name: str, input_name: str, type: DataType, default: JsonValue) Adds a required input. Supported types: string, integer, boolean, float, list, object. Example: atac_add_input("search_task", "cities", "list", ["Beijing", "Shanghai"])

• atac_add_action(name: str, id: str, action: str, args: dict, at: str | None, if_condition: str | None) Adds an action (tool call). action takes URIs like mcp://server_name/tool_name or bash://run. Note on Nested Trajectories: You can use bash://run with {"command": "atac run child_workspace"} to nest another trajectory. Example: atac_add_action("search_task", "geo", "mcp://amap-maps/maps_geo", {"address": "${city}"})

• atac_add_for(name: str, in_expr: str, item: str, at: str | None) Adds a loop. Expressions use Jinja2 syntax. Example: atac_add_for("search_task", "${inputs.cities}", "city")

• atac_add_if(name: str, condition: str, at: str | None) Adds a conditional branch. Example: atac_add_if("search_task", "${city == 'Beijing'}")

• atac_add_set(name: str, variables: dict, at: str | None) Sets or updates state variables. Example: atac_add_set("search_task", {"location": "${geo.output.content[0].text.return[0].location}"})

• atac_remove_step(name: str, at: str) Removes a specific step by its index path. Example: atac_remove_step("search_task", "0.2.then.1")

• atac_list() Lists all workspaces in the current directory along with their descriptions. Returns: A JSON array of workspace metadata.

• atac_show(name: str) Returns the trajectory JSON structure. Use this to understand current step nested paths.

• atac_run(name: str, inputs: dict, config_paths: list | None) Executes the trajectory. Returns JSON outputs.

Expression Syntax

• Inputs: ${inputs.var_name}
• Variables: ${var_name} (resolves to state variables)
• Action Outputs: ${action_id.output}
  • MCP output: ${action_id.output.content[0].text}
  • Bash output: ${action_id.output.stdout}

Example Usage

1. atac_init("demo_flow", "Demo App")
2. atac_add_input("demo_flow", "targets", "list", ["A", "B"])
3. atac_add_for("demo_flow", "${inputs.targets}", "item", None)
4. atac_add_action("demo_flow", "echo", "bash://run", {"command": "echo ${item}"}, "0", None)
5. atac_run("demo_flow", {"targets": ["X", "Y"]})