pydantic-ai

v1.98.0 Breaking

This release includes 2 breaking changes for platform teams planning a safe upgrade.

Published 16d AI Agents & Assistants

✓ No known CVEs patched

✓ No known CVEs patched in this version

Topics

agent-framework genai llm pydantic python

Summary

AI summary

Updates 🚀 Features, 🐛 Bug Fixes, and new: V2 Preparation across a mixed release.

Type	Severity	Summary	CVE
Feature	Medium	Add OpenAI Responses input token counting (OpenAIResponsesModel.count_tokens) Add OpenAI Responses input token counting (OpenAIResponsesModel.count_tokens) Source: granite4.1:8b-q6_K@2026-05-19 Confidence: high	—
Deprecation	Medium	Deprecate pydantic_ai.ext.aci (tool_from_aci and ACIToolset) Deprecate pydantic_ai.ext.aci (tool_from_aci and ACIToolset) Source: granite4.1:8b-q6_K@2026-05-19 Confidence: high	—
Bugfix	Medium	Don't require fastmcp.server at runtime in mcp module Don't require fastmcp.server at runtime in mcp module Source: granite4.1:8b-q6_K@2026-05-19 Confidence: low	—
Bugfix	Medium	Remove runtime requirement for fastmcp.server in mcp module Remove runtime requirement for fastmcp.server in mcp module Source: granite4.1:30b@2026-05-19-audit Confidence: low	—
Refactor	Medium	Replace Agent tool_retries=/output_retries= with retries: int \| AgentRetries Replace Agent tool_retries=/output_retries= with retries: int \| AgentRetries Source: granite4.1:8b-q6_K@2026-05-19 Confidence: high	—

Full changelog

Add OpenAI Responses input token counting (OpenAIResponsesModel.count_tokens) by @colesmcintosh in https://github.com/pydantic/pydantic-ai/pull/3951
Replace Agent tool_retries=/output_retries= with retries: int | AgentRetries by @Kludex in https://github.com/pydantic/pydantic-ai/pull/5500

fix(mcp): Don't require fastmcp.server at runtime by @Kymi808 in https://github.com/pydantic/pydantic-ai/pull/5514

Deprecate pydantic_ai.ext.aci (tool_from_aci and ACIToolset) by @dsfaccini in https://github.com/pydantic/pydantic-ai/pull/5510

@Kymi808 made their first contribution in https://github.com/pydantic/pydantic-ai/pull/5514

Full Changelog: https://github.com/pydantic/pydantic-ai/compare/v1.97.0...v1.98.0

Deprecation of `pydantic_ai.ext.aci` (functions `tool_from_aci` and class `ACIToolset`) — will be removed in v2.
Removal of runtime requirement for `fastmcp.server`.

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About pydantic-ai

AI Agent Framework, the Pydantic way

v1.95.0 rename ‘built-in tools’ to ‘native tools’, deprecate old fields, register via capabilities=[NativeTool(...)]