Plan

The plan server gives Aether a “plan mode” with scoped tools for writing, editing, and submitting markdown implementation plans. Agents address plans by planName; the server stores each plan as <planName>-plan.md in the configured plans directory.

Configuration

.aether/mcp.json

{
  "servers": {
    "plan": {
      "type": "in-memory"
    }
  }
}

When registered through Aether’s built-in server wiring, plans default to ${WORKSPACE}/docs/aether/plans. Standalone plan-mcp defaults to docs/aether/plans relative to its process cwd. Pass --plans-dir to override it:

.aether/mcp.json

{
  "servers": {
    "plan": {
      "type": "in-memory",
      "args": ["--plans-dir", "docs/plans"]
    }
  }
}

Pass --prompt-file to provide your own prompt for plan mode:

.aether/mcp.json

{
  "servers": {
    "plan": {
      "type": "in-memory",
      "args": ["--prompt-file", ".aether/prompts/plan-mode.md"]
    }
  }
}

Plan prompt

The server advertises one MCP prompt named plan. It accepts one required ARGUMENTS parameter containing the task to plan. Aether substitutes prompt parameters into the configured prompt body.

Submit command override

Any trailing args after plan flags are treated as an external submit command. When submit_plan is called, Aether appends the resolved absolute plan path as the final command argument and returns the command’s stdout as feedback.

.aether/mcp.json

{
  "servers": {
    "plan": {
      "type": "in-memory",
      "args": ["contextbridge", "plan", "--project", "aether"]
    }
  }
}

Without a submit command, submit_plan uses MCP elicitation and the client displays a plan review UI.

Tools

Tool	Description
write_plan	Write a named markdown plan in the configured plans directory.
edit_plan	Edit a named plan by exact string replacement.
submit_plan	Submit a named markdown plan file for review.

write_plan

Input

Field	Type	Description
planName	string	Stable plan identifier using only letters, numbers, dashes, underscores.
content	string	Markdown plan body.

Output

Field	Type	Description
planName	string	Plan identifier.
planPath	string	Absolute path written by the server.
bytesWritten	number	Number of bytes written.

edit_plan

Input

Field	Type	Description
planName	string	Stable plan identifier originally used by the plan.
oldString	string	Exact string to replace.
newString	string	Replacement string.
replaceAll	boolean	Replace every occurrence. Defaults to false.

Output

Field	Type	Description
planName	string	Plan identifier.
planPath	string	Absolute path edited by the server.
replacementsMade	number	Number of replacements made.

submit_plan

Input

Field	Type	Description
planName	string	Stable plan identifier originally used by the plan.

Output

Field	Type	Description
approved	boolean	true when the reviewer approved the plan.
feedback	string	Present when the reviewer requested changes or when an external submit command returned stdout.

Example request

{
  "planName": "docs-site-refresh"
}

Example responses

{
  "approved": true
}

{
  "approved": false,
  "feedback": "Split validation and publishing into separate steps."
}

Typical review flow

1. The planner calls write_plan with a stable plan name, such as feature.
2. The planner calls submit_plan with the same planName.
3. The client shows an approve / request-changes review form with the rendered markdown.
4. If changes are requested, the planner calls edit_plan and then submit_plan again.