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Public story · 2026-07-30 · high
The same release lets agents replay tool-search history across model providers instead of losing it mid-fallback.
Why now: Pydantic AI's follow-up release, 2.21.0, shipped July 30, right behind the MCP fix.
Pydantic AI's 2.20.0 release stops a bare McpError from killing an entire agent run, per the GitHub release notes. That's the difference between one flaky MCP server aborting a production run and the agent routing around it and continuing.
The release notes don't say whether the agent retries the failing server or just routes past it. They also don't say how many dropped servers it takes before something upstream notices.
The same release changes how provider fallback works. Tool-search history now replays across provider boundaries instead of getting dropped. An agent that switches providers mid-run keeps its search context instead of starting over.
2.20.0 also adds Claude Opus 5 support. It starts capturing Anthropic's thinking tokens in usage details too, a fuller accounting of what a run actually costs.
A second release, 2.21.0, followed on July 30. It adds a narrower guardrail: a per-request input token limit that caps how much context a single call can burn.
Each link below shares sources, entities, or timing with this story.
Claude Opus built by Anthropic / Shared entities / Same source domain / Shared topic
Linked by a graph relationship (Claude Opus built by Anthropic); both cover Anthropic, July, MCP; reported by the same outlet (github.com).
Claude Opus built by Anthropic / Shared entities / Same source domain / Shared topic / Earlier coverage
Linked by a graph relationship (Claude Opus built by Anthropic); both cover Anthropic, July, MCP; reported by the same outlet (github.com).
Claude Opus built by Anthropic / Shared entities / Earlier coverage / Tension
Linked by a graph relationship (Claude Opus built by Anthropic); both cover Anthropic, Claude Opus, July, MCP; earlier Anthropic coverage from 2026-07-23.
Claude Opus built by Anthropic / Shared entities / Same source domain / Shared topic / Earlier coverage
Linked by a graph relationship (Claude Opus built by Anthropic); both cover Anthropic, July, MCP; reported by the same outlet (github.com).
Linked by a graph relationship (Claude Opus built by Anthropic); both cover Anthropic, July, MCP; reported by the same outlet (github.com).
Claude Opus built by Anthropic / Shared entities / Same source domain / Shared topic / Earlier coverage / Tension
Linked by a graph relationship (Claude Opus built by Anthropic); both cover Anthropic, July; reported by the same outlet (github.com).
Claude Opus built by Anthropic / Shared entities / Shared topic / Earlier coverage / Tension
Linked by a graph relationship (Claude Opus built by Anthropic); both cover Anthropic, MCP; overlapping topics (agent, anthropic, claude, server).
Claude Opus built by Anthropic / Shared entities / Same source domain / Shared topic / Earlier coverage / Tension
Linked by a graph relationship (Claude Opus built by Anthropic); both cover Anthropic, Claude Opus; reported by the same outlet (github.com).