trace

Chainloop Trace: agent support

Chainloop Trace records the sessions of AI coding agents as CHAINLOOP_AI_CODING_SESSION evidence. Each agent is a provider in this package: claude/, cursor/ and opencode/. The interfaces are in provider.go, and the registry is in providers/. One provider covers OpenCode 1.x and OpenCode 2: it detects the version at runtime.

This page lists the features of Trace, by area, and tells which agents support each one. Keep it current. When you add or change a provider, or add or change a feature of Trace, update this page in the same pull request.

In the tables, Yes means supported, Partial means supported with limits, No means not supported, and Unknown means not verified. Below each table, "Why not Yes" tells the reason for each cell that is not Yes.

Claude Code has the most complete support.

Session collection

What the session evidence holds about the conversation.

Feature	What it means	Claude Code	Cursor	OpenCode 1.x	OpenCode 2
Transcript	The evidence holds the conversation (raw_session): the messages and the tool calls of the agent.	Yes	Yes	Partial	Partial
Token usage and cost	The evidence holds the tokens that the session used and their cost in USD.	Yes	No	Yes	Yes
Model detection	The evidence names the primary model and the other models that the session used.	Yes	Partial	Yes	Yes
Subagents	The evidence holds the conversations of the subagents, and their token usage, as part of the session.	Yes	No	No	No

Why not Yes:

• Transcript, OpenCode: OpenCode has no transcript file. The provider runs opencode export (1.x) or opencode session export (2) and rebuilds the transcript from the export. It keeps the text and the inputs of the tool calls. It drops the tool outputs, the reasoning and the file parts. OpenCode 2 exports also have no agent version and no session slug.
• Token usage and cost, Cursor: the Cursor transcript does not hold token usage. Usage and cost are zero, and the evidence has a warning that tells so. (For OpenCode, the cost is the value that OpenCode reports. For Claude Code, Chainloop computes it from its price table.)
• Model detection, Cursor: the primary model comes from the session-start hook. The transcript does not tell the models, so the evidence does not list the other models.
• Subagents, Cursor: the provider does not read subagent conversations.
• Subagents, OpenCode: a subagent runs in a child session with its own export. It is not part of the evidence of its parent session.

Code attribution

Which lines of a commit the AI wrote.

Feature	What it means	Claude Code	Cursor	OpenCode 1.x	OpenCode 2
Line attribution	Each changed line of a commit is attributed to the AI or to a human, from a snapshot of each file before and after the agent edits it.	Yes	Partial	Yes	Yes
Shell changes attribution	Changes that the agent makes with shell commands (for example sed) are attributed to the AI too, not only changes made with the file tools.	Yes	Partial	Yes	Yes

Why not Yes:

• Line attribution, Cursor: Cursor has only the afterFileEdit hook, which gives the edits but no snapshot before the edit. The provider rebuilds the content before the edit from the edits.
• Shell changes attribution, Cursor: the provider installs the preToolUse and postToolUse hooks for the Shell tool. These hooks are verified for the Cursor IDE only. It is not verified that the Cursor CLI sends them.

User experience

What the user sees in the agent.

Feature	What it means	Claude Code	Cursor	OpenCode 1.x	OpenCode 2
Welcome message	At session start, the user sees a message that tells that Chainloop records the session, and in which project.	Yes	No	No	No
Session link after push	After a git push that the agent runs, the user sees a link to the session in Chainloop.	Yes	No	No	No

Why not Yes:

• Welcome message, Cursor and OpenCode: the provider gives the session-start context to the model only. It has no channel that shows a message to the user at session start, so the welcome message is dropped.
• Session link after push, Cursor: the postToolUse hook runs after a shell command, but its response has no field that Cursor shows to the user. The link stays pending until it expires.
• Session link after push, OpenCode: the plugin hook fires after a shell command, but the response that shows a message to the user is not verified yet. The link stays pending until it expires.

Specs and skills

What the session was asked to build, and which skills it used.

Feature	What it means	Claude Code	Cursor	OpenCode 1.x	OpenCode 2
Spec capture instruction	At session start, the agent is told to capture the specs of the session (tickets, documents, plans, images) in the spec folder. A plan is captured only when it comes from an external source or from the plan mode of the agent: an agreement in the chat is not a plan. A pasted image is not captured, also when the agent has a file path for it. The agent tells the user in one line when it captures a file.	Yes	Yes	Yes	Yes
Spec capture reminder	At each user prompt, the agent is reminded to capture new or changed specs.	Yes	No	Yes	Yes
Local spec sources read at push	A capture whose source is a local file holds only a header and a placeholder. Each push reads the file and records its current content, so the evidence follows the edits of the file. Only a regular text file of up to 1 MiB is read. Otherwise the push keeps the body that the agent wrote, or drops the capture with a warning when there is no body (spec issue-3561).	Yes	Yes	Yes	Yes
Skills tracking	The evidence lists the skills that the session used, with a copy of each skill as it ran.	Yes	No	Partial	Partial
Spec source pointers	Exact copies of spec sources in the transcript (full file reads and file writes) are replaced with a pointer to the spec material, so the evidence does not hold the same content two or three times (spec issue-3556).	Yes	No	No	No
Pasted image pointers	Each distinct image that the user pasted into the session, including images in prompts sent while the agent was busy, is stored once as an image spec entry, from the data in the transcript, with the title "Pasted image N" and no role. A repeated paste of the same image adds no entry. The inline image in the transcript is replaced with a pointer to that material. An image whose data cannot be decoded, or that the push could not store, stays inline, and the push continues. When the agent captured the same image, its entry is kept and no second entry is added (spec issue-3569).	Yes	No	No	No

Why not Yes:

• Spec capture reminder, Cursor: Cursor has no hook at each user prompt. The agent gets the session-start instruction only.
• Skills tracking, Cursor: the provider does not track skills. The evidence has no skill entries, which means "not recorded", not "no skill used".
• Skills tracking, OpenCode: only the skills that the model starts with the skill tool are counted. Skills that the user starts, and skills used in subagents, are not.
• Spec source pointers, Cursor and OpenCode: the provider has no finder for the copies in its transcript yet. For OpenCode, the rebuilt transcript holds no tool outputs, so only the write copies would apply.
• Pasted image pointers, Cursor and OpenCode: the provider has no finder for pasted images yet. Each agent puts pasted images in a different block shape. The pasted images stay inline in the transcript. The agent is told not to capture them in the spec folder.

Security

How the evidence is protected before it leaves the machine.

Feature	What it means	Claude Code	Cursor	OpenCode 1.x	OpenCode 2
Secret redaction	Secrets in the session evidence and in the spec materials are replaced with a placeholder before upload.	Yes	Yes	Yes	Yes
Media skipped by redaction	The secret redaction does not scan base64 media (images, PDFs) in the transcript, so it is faster and does not break the media.	Yes	Unknown	Not applicable	Not applicable
Allow markers in redaction	A secret on a line that carries an inline gitleaks:allow or betterleaks:allow marker, such as a test fixture the agent read, is not redacted. The marker covers only its own line.	Yes	Yes	Yes	Yes

Why not Yes:

• Media skipped by redaction, Cursor: the redaction skips base64 media blocks of the shape {"type":"base64","data":...}. The Cursor transcript is stored as it is, and it is not verified whether it holds media in that shape.
• Media skipped by redaction, OpenCode: the rebuilt transcript holds no media.

Git integration

How the sessions are linked to the commits and attested.

Feature	What it means	Claude Code	Cursor	OpenCode 1.x	OpenCode 2
Commit trailer	Each commit gets a Chainloop-Trace-Sessions trailer with the sessions that contributed to it.	Yes	Yes	Yes	Yes
Attestation at push	The pre-push hook attests the sessions of the pushed commits.	Yes	Yes	Yes	Yes
Shell commands in another checkout	A session can work in a checkout other than the one it started in through shell commands only, for example in a fresh clone. The checkout is found from the command text: the target of cd or pushd, the path of git -C, and the folder that git clone or gh repo clone creates. The git hooks are installed there and the session is recorded there, the same as for a file tool edit in that checkout. A clone gets the git hooks only after the command that created it, so a commit in that same command does not carry the session. For OpenCode, a plugin installed by an earlier version does not send the command text: install the hooks again to update it.	Yes	Partial	Yes	Yes

Why not Yes:

• Shell commands in another checkout, Cursor: the shell hooks are verified for the Cursor IDE only. A relative path in the command resolves against the first workspace root, not against the folder where the shell runs.

How each agent is hooked in

Agent	Hook installation	Hooks
Claude Code	.claude/settings.json	Session start and end, user prompt, and before and after each file and shell tool and the Skill tool.
Cursor	.cursor/hooks.json	Session start and end, afterFileEdit, and preToolUse and postToolUse for the Shell tool. The preToolUse hook always allows the command. The provider installs no prompt hook.
OpenCode	.opencode/plugins/chainloop-trace.ts	Session start and end, user prompt, and before and after each tool. One plugin covers both versions: server() for 1.x (1.3.4 or later) and setup() for 2. The provider picks the export command from opencode --version.

All agents share the git hooks commit-msg, post-commit and pre-push.