Unclear Whether this text is actually shown to the model during a session is not clear.
What
Claude Code now contains a new piece of instruction text for the model about WebFetch, the tool that downloads a web page. It says the tool is meant for web addresses the person provided or that an earlier tool result returned. Addresses the model recalls from memory, or edits itself, may need your approval or may be rejected.
The stock description of WebFetch, as captured under this release, is unchanged.
Why
This text is meant to steer which links Claude tries to open on its own.
Names in the bundleWebFetch
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.
Added since
A small documentation edit on Intercept and control agent behavior with hooks touched a line naming WebFetch after this was published.
| `matcher` | `string` | `undefined` | Pattern matched against the event's filter field, following the [rules for matchers in settings files](/docs/en/hooks#matcher-patterns). For tool hooks, that field is the tool name. Built-in tools inc…agent-sdk/hooks see the edit
Confirmed since
Anthropic's documentation has since written up WebFetch, on Error reference.
For the network lock, the warning names `sandbox.network.allowedDomains` and `allowManagedDomainsOnly`, and says `only allowed domains (and WebFetch domain rules) from managed settings are honored`.errors see the edit
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
Whether this text is actually shown to the model during a session is not clear.
Anthropic's documentation agrees
Anthropic's documentation has since written up WebFetch, on Error reference.