Checked fact 106312 Oct 2026Agents and apps

The release notes say that "A URL that appears only in Claude's own output, the agent's system prompt, an attached document, or the output of a tool such as bash, read, or an MCP tool does not count: a web_fetch call for it returns a url_not_in_prior_context error result to the agent."

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The exact words it rests on

A URL that appears only in Claude's own output, the agent's system prompt, an attached document, or the output of a tool such as bash, read, or an MCP tool does not count: a web_fetch call for it returns a url_not_in_prior_context error result to the agent.

What the source said when we opened it, on 12 Oct 2026.

The source

Claude Platform release notes
Anthropic

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Checked

Checked by the notis newsroom on 12 Oct 2026, against the source above.

In the story

Anthropic's Claude Managed Agents web fetch tool now fetches only URLs that have already appeared in the session. 12 Oct 2026

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“The release notes say that "A URL that appears only in Claude's own output, the agent's system prompt, an attached document, or the output of a tool such as bash, read, or an MCP tool does not count: a web_fetch call for it returns a url_not_in_prior_context error result to the agent.".” ai notis, checked 12 Oct 2026. Source: Claude Platform release notes (Anthropic). https://ainotis.com/c/1063

As a reference (APA style)

ai notis. (2026, October 12). The release notes say that "A URL that appears only in Claude's own output, the agent's system prompt, an attached document, or the output of a tool such as bash, read, or an MCP tool does not count: a web_fetch call for it returns a url_not_in_prior_context error result to the agent." [Checked claim 1063]. ai notis. https://ainotis.com/c/1063

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