diff --git a/README.md b/README.md
index 1fa5d71..ad2838e 100644
--- a/README.md
+++ b/README.md
@@ -19,11 +19,20 @@ native changes, then writes the corresponding Claude Code, Codex, and OpenCode f
 | Agent prompts | Markdown body | `developer_instructions` | `prompts/<id>.md` referenced from JSON |
 | Slash commands | `~/.claude/commands/<id>.md` | `~/.codex/prompts/<id>.md` | `command.<id>` plus `command/<id>.md` |
 | Permissions | `tools` and `permissionMode` | Sandbox, approvals, and web search | Native `permission` object |
-| Per-agent skills | YAML frontmatter `skills` | Instruction hint | Native JSON `skills` array |
+| Per-agent skills | YAML frontmatter `skills` | Instruction hint | Dropped (see `docs/SKILLS.md`) |
 | Bootstrap with `shenron install` | After OpenCode | After Claude Code | Preferred import source |
 
 Shenron targets Claude Code, Codex, and OpenCode.
 
+> **Why no `skills` in OpenCode output?** OpenCode v1.x does not recognize
+> `skills` as an agent field, so the CLI forwards unknown top-level options to
+> the LLM provider as payload fields. Strict providers (Pydantic
+> `additionalProperties: false`, e.g. GLM-5.2) reject them with 400
+> `Extra inputs are not permitted`. Pivot `agents[].skills` is therefore not
+> emitted to OpenCode. Claude Code (native frontmatter) and Codex (instruction
+> hint) keep receiving the bindings, and OpenCode agents are expected to
+> reference skills from their prompt instead.
+
 ## Install
 
 Shenron requires Go 1.24 or newer.
@@ -175,14 +184,17 @@ skills:
 | `systemPrompt` / `promptFile` | Mutually exclusive. `promptFile` is relative to the pivot directory and must exist. |
 | `permissions` | Portable grants translated by each adapter. |
 | `extensions` | Target-specific overrides and fields. |
-| `skills` | Optional ordered list of kebab-case skill names, emitted as native agent metadata. Local skill existence is not required. |
+| `skills` | Optional ordered list of kebab-case skill names, emitted to Claude Code frontmatter and Codex instructions only (see below). Local skill existence is not required. |
 
 ### Per-agent skills and global skill references
 
 These two fields have different purposes:
 
-- `agents[].skills` binds skills to an agent. It round-trips through OpenCode's
-  JSON `skills` array and Claude Code's frontmatter `skills` list.
+- `agents[].skills` binds skills to an agent. It is emitted to Claude Code's
+  agent frontmatter and added as a Codex instruction hint. **OpenCode output
+  drops the field** because OpenCode v1.x forwards unknown agent keys to the
+  LLM provider, which strict providers reject (see the table note above and
+  [`docs/SKILLS.md`](docs/SKILLS.md)).
 - Top-level `skills: [{name: ...}]` stores global references only. Shenron
   does not manage skill contents or install skills on another machine.
 
diff --git a/docs/SKILLS.md b/docs/SKILLS.md
index 999c88c..d27396a 100644
--- a/docs/SKILLS.md
+++ b/docs/SKILLS.md
@@ -1,8 +1,16 @@
 # Agent skill bindings
 
 `shenron.yaml` is the source of truth for skill metadata. `shenron push <name>`
-emits each binding to both the Claude Code agent frontmatter and the OpenCode
-agent object.
+emits each binding to the **Claude Code** agent frontmatter and adds it to the
+**Codex** agent's instruction prompt.
+
+> **OpenCode output does not contain a `skills` key on generated agents.**
+> OpenCode v1.x does not recognize `skills` as an agent field, so the CLI
+> forwards unknown top-level options to the LLM provider as payload fields.
+> Strict providers (Pydantic `additionalProperties: false`, e.g. GLM-5.2)
+> reject them with HTTP 400 `Extra inputs are not permitted`. Shenron therefore
+> drops the field for OpenCode; OpenCode agents are expected to reference
+> skills from their prompt body (e.g. an `## Available skills` section).
 
 | agent | skills | file |
 |---|---|---|
diff --git a/docs/prd/shenron.md b/docs/prd/shenron.md
index 695539b..6f7595a 100644
--- a/docs/prd/shenron.md
+++ b/docs/prd/shenron.md
@@ -65,7 +65,7 @@ Chaque agent dans le pivot a les champs suivants :
 | `promptFile` | string (chemin relatif au répertoire du fichier pivot) | Non | Alternative à `systemPrompt` : référence un fichier Markdown externe contenant le prompt système. Exemple : `prompts/build.md` (relatif au répertoire où se trouve `shenron.yaml`). |
 | `permissions` | objet | Non | Permissions de l'agent (voir section dédiée) |
 | `extensions` | map string→any | Non | Champs spécifiques à un CLI cible (ex. `claudeCode.maxTurns`, `opencode.steps`). Le cœur ignore ces champs ; les adaptateurs les consomment. |
-| `skills` | list[string] (kebab-case) | Non | Skills que cet agent déclare utiliser. Référence des noms de skills dans `~/.agents/skills/`. Les adaptateurs émettent ce champ dans le format natif. |
+| `skills` | list[string] (kebab-case) | Non | Skills que cet agent déclare utiliser. Référence des noms de skills dans `~/.agents/skills/`. Émis par l'adaptateur Claude Code (frontmatter) et par l'adaptateur Codex (hint d'instruction). **Omis par l'adaptateur OpenCode** (voir décision D9). |
 
 **Règle :** `systemPrompt` et `promptFile` ne peuvent pas être spécifiés simultanément.
 
@@ -389,7 +389,7 @@ Les questions ouvertes de conception ont été résolues avant la v1.
 | D6 | Walk-up CWD→root + fallback `$HOME/.shenron/shenron.yaml`. Les deux modes (projet et global) coexistent. | FR1 |
 | D7 | Adaptateur pur + méthode `MergeFile` optionnelle dans l'interface `Adapter`. L'adaptateur OpenCode renvoie les fragments JSON pour les blocs `agent`/`command` ; le cœur fait le merge en préservant les champs hors-scope et l'indentation. | FR10 |
 | D8 | Nom du binaire : `shenron`. Distribution : binaire statique macOS/Linux via GitHub Releases + script `curl\|sh`. Pas de package npm/pip/brew en v1. | Stack |
-| D9 | Le binding skills-par-agent est désormais dans le scope v1 (amend FR2). D5 reste inchangé pour le contenu des skills, qui demeure read-only. Les adaptateurs émettent `skills` comme metadata, pas comme contenu. L'existence locale d'une skill n'est pas bloquante. | FR2, FR7, FR10 |
+| D9 | Le binding skills-par-agent est désormais dans le scope v1 (amend FR2). D5 reste inchangé pour le contenu des skills, qui demeure read-only. Les adaptateurs Claude Code et Codex émettent `skills` comme metadata ; **l'adaptateur OpenCode omet la clé `skills`** parce qu'OpenCode v1.x la forward au provider LLM en tant qu'option top-level inconnue, ce que les providers stricts (schéma Pydantic `additionalProperties: false`, ex. GLM-5.2) rejettent en 400 `Extra inputs are not permitted`. Les agents OpenCode sont censés référencer leurs skills depuis leur prompt (`## Available skills`). L'existence locale d'une skill n'est pas bloquante. | FR2, FR7, FR10 |
 | D10 | Le flux single-pivot de la v1 (`init` / `validate` / `diff` / `push` sur un `shenron.yaml` nu) a été retiré au profit du flux par package. Le contrat CLI actuel vit dans `docs/prd/scope-flatten-commands.md` : cinq commandes top-level (`install`, `list`, `update`, `diff`, `push`), `init` et `validate` supprimés, `--store` promu au niveau racine. FR1-FR4 (schéma pivot) restent valides ; FR5-FR8 sont remplacés par les FR1-FR7 du nouveau PRD. | FR5, FR6, FR7, FR8 |
 
 ## Acceptance criteria (v1)
@@ -413,7 +413,7 @@ Une session de test valide le scénario suivant :
 8. `shenron push --target opencode` → refuse d'écraser (sauf `--force`).
 9. `shenron push --target claude-code` → écrit `~/.claude/agents/build.md` à partir du même pivot, avec le frontmatter YAML Claude Code.
 10. Les permissions mappées (`edit: ask`, `bash` avec patterns) apparaissent correctement dans les deux fichiers natifs.
-11. `shenron push` round-trip un champ `skills: [foo]` modifié : il est visible dans `opencode.json` et `~/.claude/agents/<id>.md` après le push.
+11. `shenron push` round-trip un champ `skills: [foo]` modifié : il est visible dans `~/.claude/agents/<id>.md` (frontmatter) et comme instruction Codex, mais **absent de `opencode.json`** (voir décision D9).
 12. `shenron push --target codex` génère les agents TOML et prompts Markdown, puis `shenron diff --target codex` retourne "No changes".
 
 ## Stack
diff --git a/internal/adapter/opencode/adapter_test.go b/internal/adapter/opencode/adapter_test.go
index 8c21c01..82cfc35 100644
--- a/internal/adapter/opencode/adapter_test.go
+++ b/internal/adapter/opencode/adapter_test.go
@@ -82,7 +82,6 @@ func TestGenerateAgent(t *testing.T) {
 		"model":       "anthropic/claude-sonnet-4-5",
 		"temperature": 0.7,
 		"prompt":      "{file:./prompts/build.md}",
-		"skills":      []string{"test-driven-development"},
 		"steps":       50,
 		"permission": map[string]any{
 			"glob":     "allow",
@@ -106,6 +105,11 @@ func TestGenerateAgent(t *testing.T) {
 }
 
 func TestGenerateAgentSkills(t *testing.T) {
+	// OpenCode v1.x does not recognize `skills` as an agent field; the opencode
+	// CLI forwards unknown top-level options to the LLM provider as payload
+	// fields, which strict providers reject. Shenron must therefore drop the
+	// `skills` key entirely from generated OpenCode fragments, even when the
+	// pivot declares agent-level bindings.
 	agent := pivot.AgentDefinition{
 		ID:          "build",
 		Description: "Build agent",
@@ -117,9 +121,8 @@ func TestGenerateAgentSkills(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	want := []string{"test-driven-development"}
-	if !reflect.DeepEqual(fragment["skills"], want) {
-		t.Errorf("skills = %#v, want %#v", fragment["skills"], want)
+	if _, ok := fragment["skills"]; ok {
+		t.Errorf("fragment must not contain a `skills` key for OpenCode; got %#v", fragment["skills"])
 	}
 }
 
diff --git a/internal/adapter/opencode/agent.go b/internal/adapter/opencode/agent.go
index f4fb3c8..b0e68e0 100644
--- a/internal/adapter/opencode/agent.go
+++ b/internal/adapter/opencode/agent.go
@@ -42,9 +42,13 @@ func GenerateAgentFragment(agent pivot.AgentDefinition, pivotDir string) (jsonFr
 		fragment["permission"] = perms
 	}
 
-	if len(agent.Skills) > 0 {
-		fragment["skills"] = agent.Skills
-	}
+	// Pivot `agent.Skills` is intentionally NOT emitted to the OpenCode fragment.
+	// OpenCode v1.x does not recognize `skills` as an agent field, so it forwards
+	// unknown top-level options to the LLM provider as payload fields. Strict
+	// providers (e.g. GLM-5.2) reject them with 400 "Extra inputs are not
+	// permitted". Skill bindings remain available to the agent through the
+	// Claude Code and Codex adapters, and through prompt-side `## Available skills`
+	// sections authored in the pivot.
 
 	promptContent, err = resolvePromptContent(agent, pivotDir)
 	if err != nil {
diff --git a/internal/adapter/opencode/testdata/expected_opencode.json b/internal/adapter/opencode/testdata/expected_opencode.json
index 52dfcad..3de785f 100644
--- a/internal/adapter/opencode/testdata/expected_opencode.json
+++ b/internal/adapter/opencode/testdata/expected_opencode.json
@@ -16,9 +16,6 @@
         "webfetch": "deny"
       },
       "prompt": "{file:./prompts/build.md}",
-      "skills": [
-        "test-driven-development"
-      ],
       "steps": 50,
       "temperature": 0.7
     },
diff --git a/internal/cli/testdata/init/opencode/opencode.json b/internal/cli/testdata/init/opencode/opencode.json
index 97fde84..395c84e 100644
--- a/internal/cli/testdata/init/opencode/opencode.json
+++ b/internal/cli/testdata/init/opencode/opencode.json
@@ -12,7 +12,6 @@
         "lsp": "deny"
       },
       "prompt": "{file:./prompts/build.md}",
-      "skills": ["test-driven-development"],
       "steps": 50
     }
   },
diff --git a/internal/integration_test.go b/internal/integration_test.go
index 57c3a77..4704466 100644
--- a/internal/integration_test.go
+++ b/internal/integration_test.go
@@ -233,8 +233,8 @@ func TestEndToEnd_SkillsRoundTrip(t *testing.T) {
 	}
 	agents := root["agent"].(map[string]any)
 	build := agents["build"].(map[string]any)
-	if got := stringSliceValue(build["skills"]); len(got) != 1 || got[0] != "test-driven-development" {
-		t.Errorf("OpenCode build skills = %#v", got)
+	if _, ok := build["skills"]; ok {
+		t.Errorf("OpenCode build must not carry a `skills` key (forwarded to LLM providers as an unknown payload field); got %#v", build["skills"])
 	}
 	legacy := agents["legacy-helper"].(map[string]any)
 	if got := stringSliceValue(legacy["skills"]); len(got) != 1 || got[0] != "native-existing-skill" {