fix(toolintent): key the read-before-write exemption on content provenance, not parameter shape

The exemption added in 6a8a7b31 was broader than the invariant it stood on. "Tool
declares a SOURCE_PATH" is a claim about the parameter list; the safe property is
"every byte written derives from an existing source object rather than from
model-supplied content". A future transform or import tool could name a source and
still write model-controlled output, and would have inherited the exemption.

ToolCapability.CONTENT_FROM_SOURCE now carries that provenance claim explicitly.
file_copy declares it; ReadBeforeWriteRule.appliesTo stands down only for calls that
do, so ToolCallAssessor skips the rule rather than the rule skipping itself. The
capability is recorded on the invocation event like every other one, so replay
classifies a call by what it actually claimed instead of re-deriving it from
parameters.

Tool availability is by declared tool name, not capability-set containment, so the
extra capability does not narrow which stages can reach file_copy.

Tests: the exemption is asserted through ToolCallAssessor, plus a source-naming tool
WITHOUT the provenance capability that stays gated. ./gradlew check green.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

infrastructure/tools/AGENTS.md

@@ -16,7 +16,7 @@ Adapter for `core:tools`. Depends on `core:tools`, `core:events`, `core:approval
 - Web search and web fetch results are environment observations; they must be recorded as events by callers to preserve replay determinism (invariant #9).
 - `ToolConfig` is the only configuration surface; pass via `InfrastructureModule.createToolExecutor()`.
 - `buildTools()` extension on `ToolConfig` assembles the full tool list; add new tools there, not in the registry directly.
-- `file_copy` copies one existing file to another path (`{source, dest}`) so static/binary assets never pass through the model's token stream. Same jail, anchor and `fileWrite.enabled` toggle as `file_write`; `dest` is the mutated target (`ParamRole.PATH`, the only affected path), `source` is read-only (`ParamRole.SOURCE_PATH`) and may sit under an operator-granted out-of-workspace path exactly as a `file_read` may. One regular file per call: no recursion, no globs.
+- `file_copy` copies one existing file to another path (`{source, dest}`) so static/binary assets never pass through the model's token stream. Same jail, anchor and `fileWrite.enabled` toggle as `file_write`; It declares `ToolCapability.CONTENT_FROM_SOURCE` (its bytes are a faithful copy of `source`), which is what exempts it from the read-before-write gate — a tool that mixes model-authored output into its result must not declare it. `dest` is the mutated target (`ParamRole.PATH`, the only affected path), `source` is read-only (`ParamRole.SOURCE_PATH`) and may sit under an operator-granted out-of-workspace path exactly as a `file_read` may. One regular file per call: no recursion, no globs.
 - Every path parameter resolves through `ToolPath.resolve` (`core:tools`), which expands a leading `~` and anchors relatives on the bound workspace's working dir. Do not re-implement path resolution in a tool.
 - Filesystem mutation is split by intent: `file_write` only writes (`{path, content}`), `file_edit` edits, and `file_delete` only deletes (`{path}`) — deletion is a separately-named capability so a model can never delete by getting a write-mode parameter wrong. `file_delete` shares `file_write`'s path jail and `fileWrite.enabled` toggle and carries `ToolCapability.FILE_WRITE`.
 - `list_dir` is shallow by default, but collapses a non-symlink single-child directory chain (bounded depth) to the first branch point and explains that expansion in its output; recursive listings retain normal tree traversal.

infrastructure/tools/filesystem/src/main/kotlin/com/correx/infrastructure/tools/filesystem/FileCopyTool.kt

@@ -76,7 +76,11 @@ class FileCopyTool(
         )
     }
     override val tier: Tier = Tier.T2
-    override val requiredCapabilities: Set<ToolCapability> = setOf(ToolCapability.FILE_WRITE)
+    // CONTENT_FROM_SOURCE is the provenance claim: the bytes written come entirely from the file
+    // named by `source`. Declared here, recorded on the invocation event, and replayed — not
+    // re-derived from the parameter list.
+    override val requiredCapabilities: Set<ToolCapability> =
+        setOf(ToolCapability.FILE_WRITE, ToolCapability.CONTENT_FROM_SOURCE)
     override val paramRoles: Map<String, ParamRole> =
         mapOf("source" to ParamRole.SOURCE_PATH, "dest" to ParamRole.PATH)