Choosing models in GJC: role-based profiles

July 25, 2026 · View on GitHub

A practical guide to picking models for GJC's roles, for every subscription situation — one vendor, two vendors, or the full multi-vendor set. It adds curated cross-vendor profiles: for ~/.gjc/agent/models.yml and verified selector notes on top of the mechanism in Model profiles. Everything here is user config; it complements the built-in --mpreset presets and overrides a built-in only when it shares its exact name.

Selectors, prices, and "axis leaders" are catalog- and time-sensitive (selectors and prices observed 2026-07 on the current bundled catalog; the measured latency and single-message-limit notes below were observed 2026-06 on claude-opus-4-8 and have not been re-measured on claude-opus-5). Re-verify any selector with gjc -p --no-session --no-tools --model <selector> "Reply OK".

The five roles

default runs the main loop and most turns; executor / architect / planner / critic are the four bundled task agents, delegated only when the work calls for it.

Role	What it optimizes for
`default`	tool-calling reliability + honesty (it routes — its quality bounds the whole system)
`executor`	real coding (SWE-bench Verified)
`planner`	reasoning + sequencing (GPQA / ARC-AGI-2)
`architect`	large-context + multimodal review
`critic`	independent adversarial review (different family from what it reviews)

You have	Use
One vendor	the built-in preset for that vendor — `claude-opus` (Anthropic), `codex-{eco,medium,pro}` (OpenAI/Codex), `opencodego` (OpenCode Go), or a single-vendor flagship tier (`zai/glm-5.2`, `kimi-code/...`, `xiaomi/...`, `xai/grok-4.3`, `minimax-code/...`). These already map all five roles inside one vendor.
Claude + Codex	the built-in `opus-codex` (Claude main loop + Codex support roles).
Three or more / all five	the cross-vendor profiles below — each role on its axis leader, `critic` kept cross-family.

The single guiding rule across all of these: keep default on the strongest router you have (Anthropic Opus when available). A weak default caps quality regardless of the delegated models.

Cross-vendor profiles (3+ vendors)

No single vendor leads every axis, so these put each role on its axis leader and keep critic on a different family from the executor it reviews.

profiles:

  daily:                 # everyday balance
    required_providers: [anthropic, openai-codex, google-antigravity, xai]
    model_mapping:
      default:   anthropic/claude-opus-5:medium
      executor:  openai-codex/gpt-5.4:high
      planner:   google-antigravity/gemini-3.1-pro-low:high
      architect: google-antigravity/gemini-3.1-pro-low:high
      critic:    xai/grok-4.3:medium

  ultimate:              # cost-no-object, best per role
    required_providers: [anthropic, openai-codex, google-antigravity, xai]
    model_mapping:
      default:   anthropic/claude-opus-5:high
      executor:  anthropic/claude-opus-5:max
      planner:   openai-codex/gpt-5.5:xhigh
      architect: google-antigravity/gemini-3.1-pro-low:high
      critic:    xai/grok-4.3:high

  eco:                   # cheapest delegated work; main loop stays on Opus
    required_providers: [anthropic, opencode-go, google-antigravity, xai]
    model_mapping:
      default:   anthropic/claude-opus-5:low
      executor:  opencode-go/deepseek-v4-flash
      planner:   xai/grok-4-1-fast:high
      architect: google-antigravity/gemini-3.1-pro-low
      critic:    google-antigravity/gemini-3.5-flash

  monorepo:              # huge codebases (openai-codex excluded: 272k context cap)
    required_providers: [anthropic, google-antigravity, opencode-go]
    model_mapping:
      default:   anthropic/claude-opus-5:medium
      executor:  anthropic/claude-opus-5:high
      planner:   google-antigravity/gemini-3.1-pro-low:high
      architect: anthropic/claude-opus-5:high
      critic:    opencode-go/glm-5.2

  reviewer:              # review/audit stance — the author-mode role split, inverted
    required_providers: [anthropic, openai-codex, google-antigravity]
    model_mapping:
      default:   anthropic/claude-opus-5:high                 # aggregator restraint: preserve raw reviewer verdicts
      executor:  openai-codex/gpt-5.5:high                      # support — repro PoCs, failing tests, harnesses
      planner:   google-antigravity/gemini-3.1-pro-low:high     # review checklists / audit scoping
      architect: anthropic/claude-opus-5:high                 # lead 1 — primary code-review judge (effective long-context)
      critic:    openai-codex/gpt-5.5:high                      # lead 2 — merge gate, cross-family vs Claude-authored code

Reviewer stance and the external review gate

The profiles above assume an authoring stance: executor is the lead and architect/critic verify its work. In a session whose primary job is reviewing or auditing (not writing) code, the roles invert — architect/critic become the leads and executor is support (reproduction PoCs, failing tests). The reviewer profile encodes that inversion, with one generalized provenance rule: the reviewing model family must differ from the family that authored the code under review, not merely from the session's own executor.

A verified use is the cross-session final review gate: the authoring session launches a fresh, stateless reviewer sub-session so the finished diff is judged without the authoring context:

# the one-shot gate needs only a cross-family --model; add --mpreset reviewer as an
# optional enhancement AFTER installing this profile in ~/.gjc/agent/models.yml:
gjc -p --no-session --model openai-codex/gpt-5.5:xhigh --tools read,search,find "<review prompt: diff + spec paths, severity findings, final line VERDICT: APPROVE|REQUEST_CHANGES>"

The --tools allowlist is part of the contract: it enforces the reviewer's read-only boundary for the built-in tool surface instead of trusting the prompt (the runtime still injects the session goal tool unless goal.enabled is off — disabling it for the reviewer invocation is mandatory, via a dedicated gate directory outside the repo so the reviewed checkout stays clean, see the template — plus generate_image when an image credential exists). In this one-shot form the session's default model authors the verdict — a tool-restricted print session cannot delegate to the profile's critic/architect roles — so the explicit cross-family --model carries provenance, and the reviewer profile itself serves the interactive review-session case (activate it with --mpreset reviewer only after copying it into models.yml; otherwise activation fails with an unknown-profile error). Profile names in this document live in the user namespace — a user profile overrides a builtin preset only on an exact name match, and a future builtin with the same name would be silently shadowed by your copy.

See Extragoal local skill template for the full gate workflow (verdict contract, findings triage, bounded re-sign loop, secret-scan and injection guards) built on this recipe.

Model cheatsheet (by need)

Current axis leaders and the cheaper second option, with metered price ($/1M in/out; Gemini via Antigravity runs on the Google AI subscription):

Need	First pick	Cheaper option
Router / tool-calling (`default`)	`anthropic/claude-opus-5` (5/25)	`anthropic/claude-sonnet-5` (3/15)
Coding (`executor`)	`anthropic/claude-opus-5` (5/25) — the prior `claude-opus-4-8` scored SWE-bench Verified ~88.6; no Opus 5 measurement yet	`openai-codex/gpt-5.4` (2.5/15) · `opencode-go/deepseek-v4-flash` (0.14/0.28)
Reasoning (`planner`)	`openai-codex/gpt-5.5` (ARC-AGI-2) / `google-antigravity/gemini-3.1-pro-low:high` (GPQA)	`xai/grok-4-1-fast` (0.2/0.5)
Large context (`architect`)	`anthropic/claude-opus-5` (effective long-context)	`xai/grok-4-fast` (2M nominal, 0.2/0.5)
Multimodal review (`architect`)	`google-antigravity/gemini-3.1-pro-low:high`	`google-antigravity/gemini-3.5-flash`
Independent critic	`xai/grok-4.3` (1.25/2.5)	`opencode-go/glm-5.2` · `google-antigravity/gemini-3.5-flash`

On standard tasks, all current frontier models in the catalog are accurate; pick by cost, latency, and role fit, not by raw accuracy on easy prompts. As an indicative GJC-routed latency reference (gjc -p, identical coding + reasoning prompts, all correct): grok-4.3 and glm-5.2 ≈ 2–3s, deepseek-v4-pro ≈ 3–4s, claude-opus-4-8 / gpt-5.5 ≈ 4–7s, gemini-3.1-pro-low:high ≈ 7s. claude-opus-5 shares Opus 4.8's published context/output envelope but has not been latency-measured here.

Verified selector notes (current catalog)

Observed via live gjc -p calls; useful when wiring the profiles above:

Antigravity Gemini, high reasoning → use google-antigravity/gemini-3.1-pro-low:high. The id gemini-3.1-pro-high returns HTTP 400 (no matching backend model); thinkingLevel is a per-request parameter, so raising it on gemini-3.1-pro-low invokes the model's native high-reasoning mode rather than a degraded one.
openai-codex on a ChatGPT account serves base GPT only (gpt-5.5, gpt-5.4). Standalone -codex variants (gpt-5.3-codex, gpt-5.2-codex, gpt-5.1-codex-max / -mini) return not supported when using Codex with a ChatGPT account.
Single-message input limit is separate from the context window. Measured on claude-opus-4-8 (not yet re-measured on claude-opus-5, which publishes the same 1M window): the model runs with a 1M window via multi-turn accumulation, but a single @file message above ~400k tokens returns 400 on anthropic / google-antigravity; xai / opencode-go accept larger single messages. Chunk very large inputs across turns instead of pasting one block.
Some selectors come from a provider's live catalog, not the bundled snapshot. opencode-go/glm-5.2 and google-antigravity/gemini-3.5-flash resolved in gjc -p tests but are not in packages/ai/src/models.json; they appear only after the provider's online model discovery has populated the registry. required_providers verifies credentials at activation — it does not guarantee fresh, non-stale discovery — so activation can still fail with selector did not resolve until discovery runs (re-login or retry to refresh). If you hit that, substitute a bundled id: opencode-go/deepseek-v4-pro for the critic, or zai/glm-5.2 (add zai to required_providers) for GLM 5.2.

Activation

gjc --mpreset daily               # this session only
gjc --mpreset ultimate --default  # persist as the startup default (config.yml)

Activation hard-blocks when any provider in required_providers lacks credentials, so log in first: /login anthropic, /login openai-codex, /login google-antigravity, /login xai (and opencode-go via OPENCODE_API_KEY).