What
Results from the skill tool now carry an optional readOnly flag, set when a skill's instructions were loaded without anything being run. Anyone consuming skill results through the SDK or the streaming output can now tell a read-only load apart from a real execution.
Details
- New optional boolean on the skill tool's result schema, documented as true when the instructions were loaded and nothing ran.
- Not gated; it appears whenever the load was read-only.
Evidence
True when the skill instructions were loaded read-only (nothing was executed)
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Names in the bundlereadOnly
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed since
Anthropic's documentation has since written up readOnly, on Configuration reference.
| `readOnly` | `boolean` | — | Offer only read tools — the server registers no write tools at all. |third-party/claude-desktop/configuration see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up readOnly, on Configuration reference.