docs(skill): document fail-closed frontmatter validation

packages/skill/skill-local/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/skill/skill-local/README.md
-README.md: addabda98490b49736c1aa5053f5734978079a20
-README.zh.md: 1ab1a43d70d8393ba8c837f384e3a422cfdc1d3c
+README.md: 40666f8e56878260eeef13d378450273b950048d
+README.zh.md: edf3ef59539d85c903be788d063cfde74a5e16b2

packages/skill/skill-local/README.md

@@ -38,7 +38,7 @@ When `ctx.fs` is available, discovery lists roots through `ctx.fs.listDir`, read
 
 Skills can be single-level directory bundles (`<name>/SKILL.md`) or flat Markdown files (`<name>.md`). Nested `**/SKILL.md` discovery is intentionally not part of v1. Frontmatter is parsed as an open YAML object with the `yaml` package; this provider currently interprets required `name` and `description`, plus optional `whenToUse`, `metadata`, `disable-model-invocation`, and `user-invocable`. Names must be kebab-case.
 
-The two invocation fields accept YAML booleans and the case-insensitive forms `true`/`false`, `yes`/`no`, `on`/`off`, and `1`/`0`. `disable-model-invocation: true` excludes the skill from model-facing catalogs and loaders; `user-invocable: false` excludes it from human-facing commands. Each omitted field defaults to permitting its surface, and the provider always emits both positive internal policy values, including when both keys are absent. The camel-case spellings `disableModelInvocation`, `modelInvocable`, and `userInvocable` are rejected with a warning instead of acting as compatibility aliases.
+The two invocation fields accept YAML booleans and the case-insensitive forms `true`/`false`, `yes`/`no`, `on`/`off`, and `1`/`0`. `disable-model-invocation: true` excludes the skill from model-facing catalogs and loaders; `user-invocable: false` excludes it from human-facing commands. Each omitted field defaults to permitting its surface, and the provider always emits both positive internal policy values, including when both keys are absent. A rejected camel-case spelling or a non-boolean invocation value drops the entire skill from discovery with a warning instead of discarding only that field or falling back to a permissive default. Invocation policy fails closed because ignoring invalid data could expose a skill on a disabled surface; wrong-typed optional `whenToUse` and `metadata` values are omitted because neither currently grants invocation.
 
 ## Model Experience
 

packages/skill/skill-local/README.zh.md

@@ -38,7 +38,7 @@
 
 Skill 可以是单层目录 bundle（`<name>/SKILL.md`），也可以是平铺 Markdown 文件（`<name>.md`）。v1 刻意不支持发现嵌套的 `**/SKILL.md`。Frontmatter 使用 `yaml` 包解析为开放的 YAML 对象；该提供方目前解析必填的 `name` 和 `description`，以及可选的 `whenToUse`、`metadata`、`disable-model-invocation` 和 `user-invocable`。名称必须使用 kebab-case。
 
-这两个调用字段接受 YAML 布尔值，以及不区分大小写的 `true`/`false`、`yes`/`no`、`on`/`off` 和 `1`/`0`。`disable-model-invocation: true` 会从面向模型的目录和 loader 中排除该 skill；`user-invocable: false` 会从面向用户的命令中排除该 skill。每个省略的字段都默认为允许对应接口调用；提供方始终输出两个正向内部策略值，即使两个键都不存在也不例外。系统会拒绝驼峰形式的 `disableModelInvocation`、`modelInvocable` 和 `userInvocable` 并记录警告，而不会将其作为兼容别名。
+这两个调用字段接受 YAML 布尔值，以及不区分大小写的 `true`/`false`、`yes`/`no`、`on`/`off` 和 `1`/`0`。`disable-model-invocation: true` 会从面向模型的目录和 loader 中排除该 skill；`user-invocable: false` 会从面向用户的命令中排除该 skill。每个省略的字段都默认为允许对应接口调用；提供方始终输出两个正向内部策略值，即使两个键都不存在也不例外。若使用驼峰拼写或提供非布尔调用值，系统会记录警告并从发现结果中排除整个 skill，而不是只丢弃该字段或回退到宽松的默认值。调用策略校验遵循失败时默认拒绝原则，因为忽略无效数据可能会在已禁用的接口上暴露 skill；类型错误的可选 `whenToUse` 和 `metadata` 值则会被省略，因为这两个字段目前都不授予调用权限。
 
 ## 模型体验