Image Companion Skill | Agent Skills

Image Companion

Invoke with /image-companion (or whenever the user wants a slide-ready image for a passage in a document they are working on).

Supply images that belong to one artifact. The user owns a document — an article, a deck, a design doc — and points at a passage or mechanism inside it. Your job is to produce a slide-ready symbolic image that fits that spot and looks like it came from the same hand as the artifact's other images.

This is not a one-shot "make an image" tool. The relationship is lifetime companionship: across a session you may produce many images for the same artifact, and the defining duty is that they read as one set. Visual consistency is a first-class responsibility, not an afterthought.

You orchestrate two existing skills and add the human-judgment and quality layers around them. Delegate grounding to /forge and generation to the Codex CLI; your own role is the metaphor design, the human gate, verification, and series coherence.

bind artifact + passage
  → (recommended) metaphor preview gate   ← human picks the visual idea cheaply
  → /forge   (grounding + gpt-image prompt block)        [DELEGATE]
  → Codex CLI   (gpt-image-2 generation)                 [DELEGATE]
  → verify + enforce series coherence + report

Step 0 — Bind the artifact and the target

Read the artifact passage the user is pointing at. Extract the mechanism to symbolize (not just the sentence — the underlying thing it claims). This is per-call data; nothing here is fixed.

Then locate the companion set: other images already made for this artifact (same output directory, or earlier in this session). Their palette, tone, and text rules are the consistency contract for the new image. If this is the first image, you are establishing the contract — record the choices so later calls inherit them.

Carry the design-tone context forward by continuing in the same session. Compaction preserves it; that is how series coherence survives a long-running artifact.

Step 1 — Metaphor preview gate (recommended, not required)

Image generation costs real time and money. Before spending it, agree on the visual idea in plain text. This step is recommended — skip it only when the user has already named the exact metaphor.

Design 2–3 candidate metaphors for the mechanism. Keep them free of domain jargon (no SQL/JOIN/INNER/OUTER, no internal API names in the image) so an all-hands audience reads them at a glance.
Sketch each candidate as small ASCII art and put it in the preview field of an AskUserQuestion option, so the user compares the ideas in the terminal before any pixels are generated.
In the same gate, ask the loss-depiction depth when the passage describes a failure/loss: neutral (mechanism only) vs. show-through-to-the-loss (depict the bad outcome). This choice changes the image's punchline.

The ASCII preview is a cheap proxy that has repeatedly de-risked the expensive step — treat it as the default, but don't force it on a user who already knows what they want.

Step 2 — Structure the initial prompt with /forge

Invoke epistemic-cooperative:forge with the gpt-image adapter. Forge's job here is not just to "write a prompt" — it is to structure the initial prompt so that the character extracted from the artifact is preserved. Two things make up that character: the grounded essence of the passage (what the mechanism actually claims) and the companion set's identity (palette, tone, text rules). Forge encodes both into the structured prompt, so the prompt block itself becomes the carrier of artifact fidelity — not something checked back in afterward.

Forge owns the reference grounding and fills the infographic-diagram prompt schema (Use case / Asset type / Primary request / Scene / Subject / Style / Composition / Lighting / Color palette / Text verbatim / Constraints / Avoid). Hand it: the artifact passage, the chosen metaphor, the loss-depth decision, and the house-style constraints from references/house-style.md (Step 0's companion-set reading is what makes those constraints concrete). You do not write the schema yourself — forge does.

Step 3 — Generate via Codex CLI

Call the Codex CLI directly, in the same form as /review-loop's codex source and /goal-research. This runs gpt-image-2 generation as an independent model call.

Check which codex 2>/dev/null. If the Codex CLI is not found, surface the missing-binary error and stop — failure modes are raw errors, not handled internally.

Generate a unique suffix: SUFFIX=$(openssl rand -hex 4). Write forge's prompt block to /tmp/image_companion_${SUFFIX}.txt. The prompt MUST be English and MUST include the $imagegen marker so Codex engages image generation.

Launch via Bash(run_in_background: true, timeout: 600000), with --cd pointing at the artifact's image directory so the PNG lands beside its companions:

codex exec --ephemeral --json --color never --skip-git-repo-check -m gpt-5.5 \
  --config model_reasoning_effort="medium" \
  --sandbox workspace-write \
  --cd <artifact-image-dir> \
  < /tmp/image_companion_${SUFFIX}.txt \
  > /tmp/image_companion_events_${SUFFIX}.jsonl 2>/tmp/image_companion_warn_${SUFFIX}.txt

--color never + splitting the streams keeps the events file pure JSONL (stdout) and the codex banner — where the warnings ride — in its own warn file (stderr). For multiple images, launch one background call per image in the same turn so they run in parallel — each with its own ${SUFFIX}, so parallel streams never collide. Each completion sends a notification — then read that call's events file and clean up its three temp files: rm -f /tmp/image_companion_${SUFFIX}.txt /tmp/image_companion_events_${SUFFIX}.jsonl /tmp/image_companion_warn_${SUFFIX}.txt. Wait for the completion notification before reading output.

The events file is pure JSONL. Extract the final codex agent_message narrative verbatim with the line below — codex streams progress messages before the final answer, so the line takes the last agent_message — and forward it to Step 4 — the PNG-confirmation and any in-message notes you surface there are read from this narrative, not regex-parsed. If the extraction is empty, codex failed before answering — read the raw events file /tmp/image_companion_events_${SUFFIX}.jsonl for the error and surface that instead of reporting a successful generation:

jq -rs '[.[] | select(.type=="item.completed" and .item.type=="agent_message") | .item.text] | last // empty' /tmp/image_companion_events_${SUFFIX}.jsonl

Some codex warnings ride the stderr banner, not agent_message — the launch sent stderr to its own warn file. Grep that to catch what the narrative does not carry:

grep -iE 'invalid_grant|deprecat|--full-auto|warn' /tmp/image_companion_warn_${SUFFIX}.txt || true

Running in the background keeps Codex's verbose banner out of the main context. The model (-m gpt-5.5) is fixed by design — Codex substitutes its own internal image skill targeting gpt-image-2, so the model is structural, not a quality knob (see references/house-style.md). Note: --ephemeral means there is no resumable session — a correction is a fresh run with a corrective prompt, not a session resume.

Step 4 — Verify, enforce coherence, report

Read the produced PNG and run the checklist in references/verification.md. The image fails review if in-image text is not the verbatim English/numeric strings, if any CJK/SQL/JOIN text appears, if it is not landscape, or if the palette breaks the companion set's contract (two brand colors + exactly one reserved accent for the single emphasized moment).

Then produce a consolidated report in the user's language using the template in references/verification.md: a table with image, filename, and verdict, plus any non-fatal warnings (e.g., auth-token refresh notices, deprecation notices) — read from the extracted agent_message narrative (Step 3 jq line) AND from the Step 3 warn-file grep (some warnings ride the stderr banner, not the narrative) — so the user sees the full picture without reading raw codex output.

What stays fixed vs. what varies

Fixed discipline (carry into every call — details in references/house-style.md): Codex CLI run in the background, output read on notification; in-image text English/numeric only; landscape; no SQL/JOIN jargon; two brand colors + one reserved accent; fixed model.

Per-call data (never bake into the skill): the artifact path and target passage, the metaphor candidates, the loss-depth choice, the verbatim in-image strings, what the accent emphasizes, and the output filename.

Boundary

This skill forms and verifies; it delegates grounding to /forge and runs generation as a background Codex CLI call. It does not open branches or PRs.

Agent Skills: Image Companion

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