[Bug]: Amp dispatch sends -p/--model/--output-format — none of these exist in the Amp CLI #4580

Bug Description

AmpIntegration never overrides build_exec_args(), so it inherits the generic implementation from MarkdownIntegration (src/specify_cli/integrations/base.py:1062), which emits:

<exe> -p <prompt> --model <model> --output-format json

None of those three flags exist in the Amp CLI. Every workflow command:/prompt: step dispatching to Amp fails immediately at argument parsing, even with amp installed and authenticated.

This is the amp row of the audit in #2416, which lists it first among the integrations still inheriting the unverified -p / --model / --output-format json pattern.

Steps to Reproduce

1. Generate the argv Spec Kit dispatches with, from a source checkout at main (d848fb4):

$ uv run python -c "from specify_cli.integrations.amp import AmpIntegration; print(AmpIntegration().build_exec_args('hello', model='gpt-5', output_json=True))"
['amp', '-p', 'hello', '--model', 'gpt-5', '--output-format', 'json']

2. Run exactly that against the real Amp CLI:

$ amp -p "hello" --model gpt-5 --output-format json
Error: error: unknown option '-p'
$ echo $?
1

3. Confirm the flags Amp actually accepts:

$ amp --help | grep -E '^\s+-x|^\s+--stream-json$'
  -x, --execute [message]
  --stream-json

Expected Behavior

Spec Kit dispatches to Amp using Amp's documented execute-mode interface, so the command runs:

amp --execute <prompt> [--stream-json]

Actual Behavior

The dispatch fails at argument parsing with error: unknown option '-p' (exit 1). The agent is never invoked.

Checked against amp --help (v0.0.1789372854-ge954c8):

Specify CLI Version

1.0.7.dev0 (source checkout, git d848fb4)

AI Agent

Amp

Operating System

Windows 11

Python Version

3.14.7

Error Logs

$ amp -p "hello" --model gpt-5 --output-format json
Error: error: unknown option '-p'

For contrast, the proposed argv parses and proceeds (it only stops at the login prompt, because this machine has no API key):

$ amp --execute "hello" --stream-json
No API key found. Starting login flow...
To log in, visit:
https://auth.ampcode.com/device?user_code=...

Additional Context

Amp CLI version tested: 0.0.1789372854-ge954c8, installed via npx @sourcegraph/amp.

Documentation: execute mode documents -x, --execute; streaming JSON states "Use --stream-json with --execute to output streaming JSON instead of plain text."

On the model parameter: Amp exposes no model-selection flag. -m, --mode takes an agent mode (low, medium, high, ultra, or a plugin mode) which "controls the model, system prompt, and tool selection" — it is not a model identifier, so passing Spec Kit's model value through to -m would be incorrect. A fix should drop the model flag rather than remap it.

Same fix shape as the existing one-off overrides for opencode (#2409) and goose (#3781). Happy to open a PR.

AI Assistance Disclosure: AI assistance was used for the source inspection, reproduction, and drafting of this report. All CLI output above was executed and captured on the reporting machine.