ctx pro: git blame, but for agent sessions

git blame tells you which commit last changed a line. ctx blame tells you which agent session produced that commit, with exact citations back to the original transcript and recorded tool calls.

Agents use ctx blame to recover context that no longer exists anywhere near the current session. Starting from a file, line range, commit, or PR, they can find the relevant historical agent sessions and recover the decisions, constraints, failed approaches, and assumptions recorded there.

This helps agents:

• recover constraints and decisions no longer visible in the code
• uncover assumptions embedded in earlier changes
• avoid retrying approaches that already failed
• resume work without relying on lossy compaction summaries
• audit past agent work to improve instructions, tools, and workflows

Every attribution includes citations back to the original transcript and tool calls. If the session is not on your machine (for example, because a teammate's agent produced the code), ctx says it cannot prove the attribution.

# Your agent is investigating why customized cart items
# are disappearing from your e-commerce app.
$ ctx blame file src/checkout.ts --lines 118:146

# ctx blame finds the agent session that produced those lines:
# Lines 118–146
#   commit    8f3c2a1
#   Produced by
#     session   c0297b8a-2ad7-4f73-a826-8ee9387cd1f4
#     evidence  [1] [2]

# Your agent opens the transcript of the session that produced the offending commit
$ ctx show session c0297b8a-2ad7-4f73-a826-8ee9387cd1f4

# Previous agent — transcript excerpt
"Some responses contain multiple cart lines with the same product_id.
I'm treating those as duplicates and merging them before calculating the total."

# Your agent finds the mistake
"FOUND IT: The previous agent treated matching product_ids as duplicate cart lines.
Customized items can share a product ID, so that merge drops valid items."

ctx blame can also start from a commit or PR:

ctx blame commit <sha>
ctx blame pr https://github.com/your-org/your-repo/pull/42

Like ctx indexing and search capabilities, blame runs locally, so your code and history never leave your machine.

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