Expose GLM reasoning-effort tiers in the model picker

[srid]

What

Expose GLM reasoning-effort tiers in the OpenCode model picker. glm-latest
(GLM-5.2) is left exactly as on master — it reasons by default — and the same
gateway model is also surfaced at pinned effort levels you can switch between with
ctrl+x m:

Picker entry	reasoning_effort	Use it for
glm-latest	(gateway default)	the default — thinking on (unchanged)
glm-max	max	deepest reasoning
glm-high	high	strong reasoning, faster
glm-fast	none	no thinking, fastest replies

GLM-5.2 internally collapses low/medium into high, so max / high / off are the
only distinct levels — no point exposing more.

Change

coding-agents/opencode/settings/juspay.nix — mkModel gains an optional id
(wire model id when the picker key differs from the gateway name), and the GLM
family becomes:

glmLimits  = { context = 1000000; output = 32000; };   # 1M window; OpenCode caps wire max_tokens at 32000
glm-latest = glmLimits;                                # default, unchanged reasoning
glm-max    = glmLimits // { reasoningEffort = "max";  id = "glm-latest"; };
glm-high   = glmLimits // { reasoningEffort = "high"; id = "glm-latest"; };
glm-fast   = glmLimits // { reasoningEffort = "none"; id = "glm-latest"; };

All siblings target the gateway model glm-latest via id. OpenCode maps the
camelCase reasoningEffort option to the wire field reasoning_effort
(@ai-sdk/openai-compatible); snake-case in options is silently dropped and the
--variant flag is a no-op for custom providers — both verified empirically.

Proof — real OpenCode against the live gateway

1. Switching tiers in the picker (ctrl+x m), no prompt — all four entries are
selectable and the footer reflects the active one:

2. glm-max actually sends reasoning_effort: max — outgoing body captured from
the nix-generated config via a logging proxy (Authorization never logged); the wire
model is the gateway id glm-latest:

{ "model": "glm-latest", "reasoning_effort": "max", "max_tokens": 32000, "stream": true, ... }

glm-fast likewise sends reasoning_effort: "none" (verified the same way).

3. max is the real top tier, and the default is left untouched:

• Gateway validator for glm-latest (= zai-org/GLM-5.2-dev): reasoning_effort —
  "Input should be 'none', 'low', 'medium', 'high' or 'max'".
• glm-latest with no reasoning_effort (its master form) still returns
  reasoning (reasoning_tokens 119/256/99 across samples), while explicit none
  returns zero — confirming master's default is thinking-on, and this PR preserves it.

Notes

• glm-flash-experimental (GLM-4.7-Flash) only accepts up to high; left unchanged.
• Corrected context to 1000000 (the real 1M window; the old 202752 was a
  copy-paste default shared with minimax-m2/open-large). output stays 32000:
  OpenCode caps the wire max_tokens at 32000 for this custom-provider model
  regardless of limit.output (verified), so a higher value only shrinks usable
  input. Keeping the whole model table in sync with the gateway is automated in Refresh opencode model limits (context/output) from the LiteLLM gateway #82.
• Standalone NixOS tests only assert the litellm provider and bundled skills are
  present, so they're unaffected; verified the package builds and the generated
  opencode.json carries all four GLM entries with the right id/reasoningEffort.

🤖 Generated with Claude Code