diff --git a/snapshots/session/ptc-read-image-attachment-path/session.jsonl b/snapshots/session/ptc-read-image-attachment-path/session.jsonl
index c03535c239..09da819ab9 100644
--- a/snapshots/session/ptc-read-image-attachment-path/session.jsonl
+++ b/snapshots/session/ptc-read-image-attachment-path/session.jsonl
@@ -15,7 +15,7 @@
 {"type":"assistant/chunk","data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":0,"block":{"type":"tool-call","id":"code-image-source","name":"run_code","arguments":"{\"code\":\"return await tools.read_image({ file_path: 'red.png' })\",\"description\":\"Read the source image\"}"}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":3,"outputTokens":3}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","data":{"turn":1,"step":1,"message":{"role":"assistant","content":[{"type":"tool-call","id":"code-image-source","name":"run_code","arguments":"{\"code\":\"return await tools.read_image({ file_path: 'red.png' })\",\"description\":\"Read the source image\"}"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:3}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[[12,15]],"surfaceOp":"append"}
+{"type":"assistant/message","data":{"turn":1,"step":1,"message":{"role":"assistant","content":[{"type":"tool-call","id":"code-image-source","name":"run_code","arguments":"{\"code\":\"return await tools.read_image({ file_path: 'red.png' })\",\"description\":\"Read the source image\"}"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:3}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[12,13,14,15],"surfaceOp":"append"}
 {"type":"tool/call","data":{"turn":1,"step":1,"callId":"code-image-source","name":"run_code","arguments":"{\"code\":\"return await tools.read_image({ file_path: 'red.png' })\",\"description\":\"Read the source image\"}"}}
 {"type":"tool/code-dispatch-start","data":{"rootCallId":"code-image-source","parentCallId":"code-image-source","subCallId":"code-image-source:code:1","name":"read_image","arguments":{"file_path":"red.png"}}}
 {"type":"tool/code-dispatch","data":{"rootCallId":"code-image-source","parentCallId":"code-image-source","subCallId":"code-image-source:code:1","name":"read_image","arguments":{"file_path":"red.png"},"isError":false,"content":[{"type":"text","text":"<path>{{cwd}}/red.png</path>\n<type>image</type>\n<content>\nimage/png image, 1x1 px, 69 bytes\n</content>"},{"type":"image","attachment":{"attachmentId":"sha256:b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640","mediaType":"image/png","bytes":69,"width":1,"height":1,"name":"red.png"}}]}}
@@ -29,7 +29,7 @@
 {"type":"assistant/chunk","data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":0,"block":{"type":"tool-call","id":"code-image-object","name":"run_code","arguments":"{\"code\":\"return await tools.read_image({ file_path: '{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640' })\",\"description\":\"Read the normalized attachment object directly\"}"}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":3,"outputTokens":3}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","data":{"turn":1,"step":2,"message":{"role":"assistant","content":[{"type":"tool-call","id":"code-image-object","name":"run_code","arguments":"{\"code\":\"return await tools.read_image({ file_path: '{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640' })\",\"description\":\"Read the normalized attachment object directly\"}"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:6}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[[26,29]],"surfaceOp":"append"}
+{"type":"assistant/message","data":{"turn":1,"step":2,"message":{"role":"assistant","content":[{"type":"tool-call","id":"code-image-object","name":"run_code","arguments":"{\"code\":\"return await tools.read_image({ file_path: '{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640' })\",\"description\":\"Read the normalized attachment object directly\"}"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:6}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[26,27,28,29],"surfaceOp":"append"}
 {"type":"tool/call","data":{"turn":1,"step":2,"callId":"code-image-object","name":"run_code","arguments":"{\"code\":\"return await tools.read_image({ file_path: '{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640' })\",\"description\":\"Read the normalized attachment object directly\"}"}}
 {"type":"tool/code-dispatch-start","data":{"rootCallId":"code-image-object","parentCallId":"code-image-object","subCallId":"code-image-object:code:1","name":"read_image","arguments":{"file_path":"{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640"}}}
 {"type":"tool/code-dispatch","data":{"rootCallId":"code-image-object","parentCallId":"code-image-object","subCallId":"code-image-object:code:1","name":"read_image","arguments":{"file_path":"{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640"},"isError":false,"content":[{"type":"text","text":"<path>{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640</path>\n<type>image</type>\n<content>\nimage/png image, 1x1 px, 69 bytes\n</content>"},{"type":"image","attachment":{"attachmentId":"sha256:b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640","mediaType":"image/png","bytes":69,"width":1,"height":1,"name":"b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640"}}]}}
@@ -43,6 +43,6 @@
 {"type":"assistant/chunk","data":{"turn":1,"step":3,"chunk":{"type":"block-end","index":0,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":3,"chunk":{"type":"usage","usage":{"inputTokens":3,"outputTokens":3}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":3,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","data":{"turn":1,"step":3,"message":{"role":"assistant","content":[{"type":"text","text":"DONE"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:9}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[[40,43]],"surfaceOp":"append"}
+{"type":"assistant/message","data":{"turn":1,"step":3,"message":{"role":"assistant","content":[{"type":"text","text":"DONE"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:9}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[40,41,42,43],"surfaceOp":"append"}
 {"type":"step/end","data":{"turn":1,"step":3}}
 {"type":"turn/end","data":{"turn":1,"reason":{"kind":"completed"}}}
diff --git a/snapshots/session/read-image-attachment-path/session.jsonl b/snapshots/session/read-image-attachment-path/session.jsonl
index 4ea43a90dc..aabb815515 100644
--- a/snapshots/session/read-image-attachment-path/session.jsonl
+++ b/snapshots/session/read-image-attachment-path/session.jsonl
@@ -15,7 +15,7 @@
 {"type":"assistant/chunk","data":{"turn":1,"step":1,"chunk":{"type":"block-end","index":0,"block":{"type":"tool-call","id":"read-image-source","name":"read_image","arguments":"{\"file_path\":\"red.png\"}"}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":1,"chunk":{"type":"usage","usage":{"inputTokens":3,"outputTokens":3}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":1,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","data":{"turn":1,"step":1,"message":{"role":"assistant","content":[{"type":"tool-call","id":"read-image-source","name":"read_image","arguments":"{\"file_path\":\"red.png\"}"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:3}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[[12,15]],"surfaceOp":"append"}
+{"type":"assistant/message","data":{"turn":1,"step":1,"message":{"role":"assistant","content":[{"type":"tool-call","id":"read-image-source","name":"read_image","arguments":"{\"file_path\":\"red.png\"}"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:3}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[12,13,14,15],"surfaceOp":"append"}
 {"type":"tool/call","data":{"turn":1,"step":1,"callId":"read-image-source","name":"read_image","arguments":"{\"file_path\":\"red.png\"}"}}
 {"type":"tool/result","data":{"turn":1,"step":1,"message":{"source":{"kind":"tool","callId":"read-image-source"},"content":[{"type":"tool-result","toolCallId":"read-image-source","content":[{"type":"text","text":"<path>{{cwd}}/red.png</path>\n<type>image</type>\n<content>\nimage/png image, 1x1 px, 69 bytes\n</content>"},{"type":"image","attachment":{"attachmentId":"sha256:b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640","mediaType":"image/png","bytes":69,"width":1,"height":1,"name":"red.png"}}],"isError":false}],"role":"user","id":"{{message:4}}"}},"sourceEventSeqs":[17],"surfaceOp":"append"}
 {"type":"step/end","data":{"turn":1,"step":1}}
@@ -24,7 +24,7 @@
 {"type":"assistant/chunk","data":{"turn":1,"step":2,"chunk":{"type":"block-end","index":0,"block":{"type":"tool-call","id":"read-image-object","name":"read_image","arguments":"{\"file_path\":\"{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640\"}"}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":2,"chunk":{"type":"usage","usage":{"inputTokens":3,"outputTokens":3}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":2,"chunk":{"type":"finish","reason":{"kind":"tool-calls"}}}}
-{"type":"assistant/message","data":{"turn":1,"step":2,"message":{"role":"assistant","content":[{"type":"tool-call","id":"read-image-object","name":"read_image","arguments":"{\"file_path\":\"{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640\"}"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:5}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[[21,24]],"surfaceOp":"append"}
+{"type":"assistant/message","data":{"turn":1,"step":2,"message":{"role":"assistant","content":[{"type":"tool-call","id":"read-image-object","name":"read_image","arguments":"{\"file_path\":\"{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640\"}"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:5}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[21,22,23,24],"surfaceOp":"append"}
 {"type":"tool/call","data":{"turn":1,"step":2,"callId":"read-image-object","name":"read_image","arguments":"{\"file_path\":\"{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640\"}"}}
 {"type":"tool/result","data":{"turn":1,"step":2,"message":{"source":{"kind":"tool","callId":"read-image-object"},"content":[{"type":"tool-result","toolCallId":"read-image-object","content":[{"type":"text","text":"<path>{{cwd}}/.dsh/attachments/v1/objects/b1/b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640</path>\n<type>image</type>\n<content>\nimage/png image, 1x1 px, 69 bytes\n</content>"},{"type":"image","attachment":{"attachmentId":"sha256:b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640","mediaType":"image/png","bytes":69,"width":1,"height":1,"name":"b1ff9c8ea3a780bad09b346c423d2d0e46815926879b18e841d928376a946640"}}],"isError":false}],"role":"user","id":"{{message:6}}"}},"sourceEventSeqs":[26],"surfaceOp":"append"}
 {"type":"step/end","data":{"turn":1,"step":2}}
@@ -33,6 +33,6 @@
 {"type":"assistant/chunk","data":{"turn":1,"step":3,"chunk":{"type":"block-end","index":0,"block":{"type":"text","text":"DONE"}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":3,"chunk":{"type":"usage","usage":{"inputTokens":3,"outputTokens":3}}}}
 {"type":"assistant/chunk","data":{"turn":1,"step":3,"chunk":{"type":"finish","reason":{"kind":"stop"}}}}
-{"type":"assistant/message","data":{"turn":1,"step":3,"message":{"role":"assistant","content":[{"type":"text","text":"DONE"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:7}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[[30,33]],"surfaceOp":"append"}
+{"type":"assistant/message","data":{"turn":1,"step":3,"message":{"role":"assistant","content":[{"type":"text","text":"DONE"}],"source":{"kind":"model","provider":"deepseek-official","model":"deepseek-v4-flash-vision-exp"},"id":"{{message:7}}"},"usage":{"inputTokens":3,"outputTokens":3}},"sourceEventSeqs":[30,31,32,33],"surfaceOp":"append"}
 {"type":"step/end","data":{"turn":1,"step":3}}
 {"type":"turn/end","data":{"turn":1,"reason":{"kind":"completed"}}}