A change request (CR) merges one git branch into another. SingulaComp creates a CR from a session's branch (head_ref) onto the project's default branch (base_ref, usually main). The CR row is metadata; the merge, diff, and conflict checks run as real git operations against the project's repository. A CR is the only way session work reaches the default branch.

Why work goes through a CR

A session runs in a sandbox on its own branch, named after the session ID. The sandbox does not last forever, but the branch does: git is the only durable record of a session's work. Every new session starts from the default branch. Until a CR merges, the work stays on its own branch, unreviewed and invisible to every other agent, trigger, and collaborator. This applies to every change: code, agents, skills, and the manifest (singulacomp.yaml) — no exceptions.

The agent mandate

An agent must open a CR to land any change on the project's default branch. The agent does not merge its own CR — merging is the user's decision. Follow this contract:

Commit on the session branch ($SINGULACOMP_BRANCH_NAME). Make small, working commits. Do not rewrite history or force-push.
Push the branch: git push origin HEAD.
Open the CR: singulacomp cr open --title "..." --description "...". Inside a session sandbox, --head and --session default to $SINGULACOMP_BRANCH_NAME and $SINGULACOMP_SESSION_ID. --base defaults to the project's default branch.
Tell the user the CR number, so they can review it.
Stop. Do not merge the CR yourself.

Anti-patterns

Force-pushing to the default branch. This breaks the review contract, even where the backend allows it.
"It's on my branch, pull it yourself." The session branch is gone once the sandbox stops, unless a CR merged it first.
Sending the change as a file, paste, or archive. The CR system already solves this problem.

Data model

CRs live in the change_requests table.

Column	Type	Notes
`cr_id`	uuid	Primary key. The REST API's identifier.
`project_id`	uuid	The project the CR belongs to.
`number`	integer	Per-project display number (`#1`, `#2`…). Unique per project. Never recycles.
`title`	text	Required.
`description`	text	Defaults to an empty string.
`base_ref`	text	The branch merged into. Usually `main`.
`head_ref`	text	The branch merged from. In a session, this is the session ID (a UUID).
`status`	enum	`open`, `merged`, or `closed`.
`head_commit_sha`	text	Refreshed against the live `head_ref` tip on every read, for open CRs. Captured at merge time for merged CRs.
`base_commit_sha`	text	Same rule, for `base_ref`.
`origin_session_id`	text	The session that opened the CR. Set to null if that session is deleted.
`created_by`	uuid	The user who created the CR.
`merged_at` / `merged_by`	timestamp / uuid	When and who merged the CR.
`merge_commit_sha`	text	The merge commit. Equals `head_commit_sha` for a fast-forward.
`closed_at` / `closed_by`	timestamp / uuid	When and who closed the CR without merging.
`metadata`	jsonb	Holds `requested_changes`, a list of `{text, by, at}` entries added by `POST /:crId/request-changes`. CRs have no separate comment table.
`created_at` / `updated_at`	timestamp	Set on creation. Updated on every status change or SHA refresh.

A unique index on (project_id, number) lets you reference a CR by its short number instead of its UUID.

Lifecycle

text

open ──(merge)──▶ merged      (terminal)
open ──(close)──▶ closed ──(reopen)──▶ open

open is the starting status.
closed is reversible. POST /:crId/reopen sets it back to open.
merged is terminal. You cannot reopen or close a merged CR. Open a new CR against the merged state instead.

SingulaComp refuses to create a CR whose branch has no commits ahead of the default branch. This usually means the agent committed locally but never pushed. Push the commits, then create the CR again.

SHA refresh

For an open CR, SingulaComp refreshes head_commit_sha and base_commit_sha against the live branches on every GET. If the repository is unreachable, or a branch is missing, SingulaComp skips the refresh and serves the CR's last known metadata. A merged CR keeps the SHAs captured at merge time — SingulaComp never refreshes them again.

Merge mechanics

POST /v1/projects/:projectId/change-requests/:crId/merge runs these steps.

SingulaComp reads the manifest (singulacomp.yaml) from head_ref and validates it against the manifest schema. A branch with no manifest passes. An invalid manifest returns 422 with code: "MANIFEST_INVALID" and stops the merge.
SingulaComp fast-forwards base_ref if head_ref is strictly ahead of it.
Otherwise, SingulaComp creates a merge commit. The default message is Merge CR #<n>: <title>, and you can override it with message in the request body. The commit author is SingulaComp <[email protected]>.
A conflict returns 409 with the conflict list. Check the same list with GET /:crId/merge-preview before you merge.
On success, SingulaComp sets status to merged, records merged_at, merged_by, and merge_commit_sha, and invalidates the project's git cache.

Merging a CR that is not open returns 409.

Merge preview

GET /:crId/merge-preview returns:

Field	Type	Meaning
`base_sha`	string	Current tip of `base_ref`.
`head_sha`	string	Current tip of `head_ref`.
`merge_base`	string \| null	Common ancestor. Null if the histories are unrelated.
`is_up_to_date`	boolean	`head_ref` is fully merged into `base_ref`.
`can_merge`	boolean	No conflicts.
`can_fast_forward`	boolean	`head_ref` is strictly ahead of `base_ref`.
`conflicts`	string[]	File paths that would conflict.

REST API

All routes sit under /v1/projects/:projectId/change-requests.

Method	Path	Notes
GET	`/`	`?status=open\|merged\|closed\|all`. No filter returns every status.
POST	`/`	Body: `{title, description?, head_ref, base_ref?, session_id?}`. Returns `201`.
GET	`/:crId`	Returns the CR. Refreshes SHAs as a side effect.
PATCH	`/:crId`	Edits `title` or `description`. `409` if not `open`.
GET	`/:crId/diff`	Unified patch: file list, additions, deletions.
GET	`/:crId/merge-preview`	See Merge preview above.
POST	`/:crId/merge`	Body: `{message?}`. `422` on an invalid manifest. `409` on conflict or if not `open`.
POST	`/:crId/close`	`409` if already `merged`.
POST	`/:crId/reopen`	`409` if not `closed`.
POST	`/:crId/request-changes`	Body: `{feedback}`. Appends to `metadata.requested_changes` and wakes the originating session's agent. `409` if not `open`.

POST / rejects a head_ref with no commits ahead of base_ref: 422 code: "CR_HEAD_NOT_AHEAD". This is the error an agent sees if it opens a CR before pushing its branch.

Authorization

Read routes need read access to the project. Write routes need write access. Each write action also needs a capability, shown below for a full token and for a session's scoped token.

Action	Capability
Open a CR	`project.gitops.push`
Request changes	`project.review.act`
Merge	`project.gitops.merge`

One capability per action, for a full token and a session's scoped token alike. Opening and merging are separate leaves, so a token can open change requests without the power to merge them — that is the mechanism behind the agent mandate above.

project.cr.open and project.cr.merge were the pre-cutover names for project.gitops.push and project.gitops.merge — the same capability under a second name. A singulacomp.yaml that still lists one keeps working (the grant is rewritten to the live spelling when it is resolved), but write the gitops name in anything new.

A session can never merge a change request it opened itself, whatever it has been granted. That rule is structural, not a capability.

Change requests