1.0.0

Agent Client Protocol Python SDK 1.0.0 is the first stable 1.x release.

Highlights

• Stable ACP v1 bindings now track schema-v1.23.0, with the missing v1 protocol methods, stable session/resume and session/close routing, and request cancellation via $/cancel_request.
• Experimental ACP v2 bindings and runtime track schema-v2.0.0-alpha.5, with protocol negotiation and support over stdio, Streamable HTTP, and WebSocket.
• More robust transport handling: malformed and non-object JSON-RPC frames, invalid response IDs, SSE UTF-8 boundaries, and error responses are handled consistently.
• Session snapshots isolate raw tool payloads, explicitly empty permission options are rejected, and subprocess shutdown bounds stdin closure.
• Package support extends to Python 3.15 (Python requirement: >=3.10,<3.16), with dependency security updates.

Upgrading from 0.12.x

This is a major release with API changes. Review these before upgrading:

• The acp.helpers module and its top-level builder exports have been removed. Construct generated models from acp.schema directly; discriminator fields have defaults. For example, replace text_block("Hello") with TextContentBlock(text="Hello") imported from acp.schema.
• Review v1 schema changes, including session notice capabilities, the stable tool-call name field, TerminalAuthMethod replacing EnvVarAuthMethod, and stricter accepted elicitation content. See the quickstart.
• Experimental v2 connection methods and handlers use expanded snake-case parameters, for example connection.new_session(cwd="/workspace"). See the v2 guide.
• Web transports use Starlette and httpx2[http2]. Install agent-client-protocol[http] for those optional dependencies. See the web transport guide.

The stable SDK version does not change the experimental status of protocol v2 or the web transports.

pip install --upgrade agent-client-protocol==1.0.0

What's Changed

• fix: handle UTF-8 split across SSE chunks by @Excelius-Wang in #135
• refactor(codegen): generate schema bindings directly by @PsiACE in #136
• refactor: remove schema helper API by @PsiACE in #137
• feat(schema): update to 1.21.0 by @PsiACE in #138
• refactor(codegen): separate v1 schema semantics by @PsiACE in #140
• feat(codegen): generate experimental v2 bindings by @PsiACE in #141
• feat(v2): add experimental runtime and negotiation by @PsiACE in #139
• refactor: simplify web transports with Starlette by @frostming in #142
• chore: migrate HTTP client dependency from httpx to httpx2 by @frostming in #143
• chore(deps): bump anyio from 4.14.1 to 4.14.2 in the uv group across 1 directory by @dependabot[bot] in #145
• feat(schema)!: bump ACP v1 schema to 1.23.0 by @PsiACE in #146
• feat(v2)!: bump ACP draft schema to 2.0.0-alpha.5 by @PsiACE in #147
• feat: complete missing v1 protocol methods by @frostming in #148
• refactor: derive routers from protocol metadata by @frostming in #149
• refactor(v2)!: expand parameters and derive routes from protocols by @frostming in #150
• chore(deps): bump urllib3 from 2.7.0 to 2.8.0 in the uv group across 1 directory by @dependabot[bot] in #164
• chore(deps): bump virtualenv from 20.36.1 to 21.7.13 in the uv group across 1 directory by @dependabot[bot] in #165
• fix: make the schema codegen host-independent by @PerryLink in #151
• fix: bound stdin closure during subprocess shutdown by @Oscar-Williams in #152
• fix: align AgentSideConnection.to_agent type with AgentFactory by @extreme-structure in #157
• fix: route stable session/resume and session/close by @monody0007 in #159
• fix(contrib): reject explicitly empty permission options by @monody0007 in #156
• fix(connection): support $/cancel_request request cancellation by @monody0007 in #158
• fix(ws): warn when the server ignores binary frames by @frostming in #166
• feat(http): serve v2 over Streamable HTTP and WebSocket by @odellus in #163
• fix(transport): ignore JSON-RPC frames that are not objects by @PerryLink in #153
• fix: isolate raw tool payloads in session snapshots by @ningyixi in #171
• fix(ws): ignore non-object JSON frames in client transport by @CHLIN0 in #169
• fix(connection): ignore responses whose id is not a RequestId by @PerryLink in #167
• fix(http): skip non-object JSON in SSE streams by @ningyixi in #172
• feat: support Python 3.15 by @daeho-ro in #173
• chore(deps): bump dev tooling for security advisories by @benbrandt in #178
• fix: align JSON-RPC error handling across transports by @PsiACE in #174
• chore(deps): bump the uv group across 1 directory with 2 updates by @dependabot[bot] in #180
• chore(deps): bump virtualenv from 21.14.12 to 21.14.13 in the uv group across 1 directory by @dependabot[bot] in #181

New Contributors

• @Excelius-Wang made their first contribution in #135
• @PerryLink made their first contribution in #151
• @Oscar-Williams made their first contribution in #152
• @extreme-structure made their first contribution in #157
• @monody0007 made their first contribution in #159
• @odellus made their first contribution in #163
• @ningyixi made their first contribution in #171
• @CHLIN0 made their first contribution in #169
• @daeho-ro made their first contribution in #173
• @benbrandt made their first contribution in #178

Full Changelog: 0.12.1...1.0.0

1.0.0rc3

What's Changed

• chore(deps): bump urllib3 from 2.7.0 to 2.8.0 in the uv group across 1 directory by @dependabot[bot] in #164
• chore(deps): bump virtualenv from 20.36.1 to 21.7.13 in the uv group across 1 directory by @dependabot[bot] in #165
• fix: make the schema codegen host-independent by @PerryLink in #151
• fix: bound stdin closure during subprocess shutdown by @Oscar-Williams in #152
• fix: align AgentSideConnection.to_agent type with AgentFactory by @extreme-structure in #157
• fix: route stable session/resume and session/close by @monody0007 in #159
• fix(contrib): reject explicitly empty permission options by @monody0007 in #156
• fix(connection): support $/cancel_request request cancellation by @monody0007 in #158
• fix(ws): warn when the server ignores binary frames by @frostming in #166
• feat(http): serve v2 over Streamable HTTP and WebSocket by @odellus in #163
• fix(transport): ignore JSON-RPC frames that are not objects by @PerryLink in #153

New Contributors

• @PerryLink made their first contribution in #151
• @Oscar-Williams made their first contribution in #152
• @extreme-structure made their first contribution in #157
• @monody0007 made their first contribution in #159
• @odellus made their first contribution in #163

Full Changelog: 1.0.0rc2...1.0.0rc3

v1.0.0rc2

What's Changed

• chore: migrate HTTP client dependency from httpx to httpx2 by @frostming in #143
• chore(deps): bump anyio from 4.14.1 to 4.14.2 in the uv group across 1 directory by @dependabot[bot] in #145
• feat(schema)!: bump ACP v1 schema to 1.23.0 by @PsiACE in #146
• feat(v2)!: bump ACP draft schema to 2.0.0-alpha.5 by @PsiACE in #147
• feat: complete missing v1 protocol methods by @frostming in #148
• refactor: derive routers from protocol metadata by @frostming in #149
• refactor(v2)!: expand parameters and derive routes from protocols by @frostming in #150

Full Changelog: 1.0.0rc1...1.0.0rc2

v1.0.0 RC1

What's Changed

• fix: handle UTF-8 split across SSE chunks by @Excelius-Wang in #135
• refactor(codegen): generate schema bindings directly by @PsiACE in #136
• refactor: remove schema helper API by @PsiACE in #137
• feat(schema): update to 1.21.0 by @PsiACE in #138
• refactor(codegen): separate v1 schema semantics by @PsiACE in #140
• feat(codegen): generate experimental v2 bindings by @PsiACE in #141
• feat(v2): add experimental runtime and negotiation by @PsiACE in #139
• refactor: simplify web transports with Starlette by @frostming in #142

New Contributors

• @Excelius-Wang made their first contribution in #135

Full Changelog: 0.12.1...1.0.0rc1

0.12.1

What's Changed

• fix(codegen): support datamodel-code-generator 0.71 by @PsiACE in #127
• chore(deps): bump h2 from 4.3.0 to 4.4.1 in the uv group across 1 directory by @dependabot[bot] in #131
• refactor(connection): simplify connection handling and remove unused components by @frostming in #132
• chore(deps): bump pymdown-extensions from 11.0 to 11.0.1 in the uv group across 1 directory by @dependabot[bot] in #133
• fix(connection): preserve notification response ordering by @hallerite in #129

New Contributors

• @hallerite made their first contribution in #129

Full Changelog: 0.12.0...0.12.1

0.12.0

What's Changed

• feat(schema): bump ACP schema to v1.19.0 (extensible unions + lenient deserialization) by @michelTho in #117
• RFD-based ACP HTTP and WS web transport implementation by @federicociner in #118
• chore(deps-dev): bump datamodel-code-generator from 0.35.0 to 0.64.0 in the uv group across 1 directory by @dependabot[bot] in #123
• release: 0.12.0 by @PsiACE in #124

New Contributors

• @federicociner made their first contribution in #118

Full Changelog: 0.11.1...0.12.0

0.11.1

What's Changed

• fix(connection): log unhandled RPC handler exceptions by @michelTho in #116
• package scritps/ directory as well by @mcepl in #120
• chore(deps): bump pymdown-extensions from 10.21.3 to 11.0 in the uv group across 1 directory by @dependabot[bot] in #121
• chore: bump version to 0.11.1 by @PsiACE in #122

New Contributors

• @mcepl made their first contribution in #120

Full Changelog: 0.11.0...0.11.1

0.11.0

What's Changed

• chore(deps): bump uv from 0.11.6 to 0.11.15 in the uv group across 1 directory by @dependabot[bot] in #107
• feat: update ACP schema to v0.13.3 by @PsiACE in #106
• feat: update ACP schema to v0.13.6 by @PsiACE in #110
• fix: recover from oversized JSON-RPC frames by @PsiACE in #111
• fix: close run_agent connection on cancellation by @PsiACE in #113
• feat(schema): bump ACP schema to v1.16.0 by @PsiACE in #114

Full Changelog: 0.10.1...0.11.0

0.10.1

What's Changed

• chore(deps): bump urllib3 from 2.6.3 to 2.7.0 in the uv group across 1 directory by @dependabot[bot] in #96
• chore(deps): bump pymdown-extensions from 10.16.1 to 10.21.3 in the uv group across 1 directory by @dependabot[bot] in #99
• chore(deps): bump idna from 3.11 to 3.15 in the uv group across 1 directory by @dependabot[bot] in #100
• fix(examples): improve gemini.py CLI experience by @whhe in #103
• fix: assign receive-loop attributes before spawning recv task by @SAY-5 in #102
• release: 0.10.1 by @PsiACE in #104

New Contributors

• @whhe made their first contribution in #103
• @SAY-5 made their first contribution in #102

Full Changelog: 0.10.0...0.10.1

0.10.0

What's Changed

• chore(deps): bump uv from 0.9.7 to 0.11.6 in the uv group across 1 directory by @dependabot[bot] in #88
• chore(deps-dev): bump pytest from 8.4.2 to 9.0.3 in the uv group across 1 directory by @dependabot[bot] in #89
• fix: reject pending requests on EOF to prevent infinite hang by @simonrosenberg in #86
• chore(deps-dev): bump python-dotenv from 1.2.1 to 1.2.2 in the uv group across 1 directory by @dependabot[bot] in #90
• feat: bump acp protocol to 0.12.2 by @PsiACE in #93
• fix(schema): coerce string protocolVersion in InitializeRequest by @WeeeeeKdY in #92
• fix: skip blank/whitespace lines in receive loop by @aorumbayev in #87
• feat: add receive_timeout parameter to Connection class by @birdg0 in #84

New Contributors

• @simonrosenberg made their first contribution in #86
• @WeeeeeKdY made their first contribution in #92
• @aorumbayev made their first contribution in #87
• @birdg0 made their first contribution in #84

Full Changelog: 0.9.0...0.10.0