> ## Documentation Index > Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt > Use this file to discover all available pages before exploring further. # Read what a session changed on disk > The files this session's write, edit and delete tools changed, each with what it did to the file, how many lines moved, and the content the file held before the session first touched it. It is what a diff view of a session's own work stands on, and what a touched-files list shows counts from. Every row is measured from FIRST touch. A file the session edited five times is one row comparing what it held before edit one against what is on disk now — not five rows, and not the last edit's delta. That is also why a file put back the way it was is absent from the answer: it changed nothing, and reporting it at zero lines either way would claim otherwise. The current content is deliberately not served. The host and its clients share a filesystem, so a client reads the file itself and gets the version it is about to let somebody edit, rather than a copy that was already stale when it was sent. What only the host has is the before side. Both sides are bounded at 1 MiB (1048576 bytes). Past that nothing was kept, and the row says so through beforeState rather than serving an empty file or a truncated one: beforeBytes still carries the real size, so a client can say how large the file it cannot diff is. linesAdded and linesRemoved are then absent, because a count nobody could compute is not zero. ## OpenAPI ````yaml /en/openapi/v3-current/narya.yaml get /v1/sessions/{sessionId}/changes openapi: 3.1.0 info: title: Narya Host API version: 1.0.0 description: >- The contract between the Narya host and every client. One long-lived host runs on your machine and serves this API over a Unix socket in your Narya home. Narya creates the socket owner-only, and file permissions are the whole authorization. There is no password, no token and no TLS. The terminal client and the one-shot command that Lerian ships drive this API, and a client you write drives the same one. Results never arrive on the response of the request that caused them. Submitting a message returns 202 with a turn id. Everything the turn produces streams over GET /v1/events as server-sent events with a typed envelope, and a stream resumes from a Last-Event-ID header. One error envelope: code, title, message, and fields on 422. Codes are NRY- followed by four digits. A paged list answers items, limit and a nextCursor when more remains. Cursors are opaque. servers: [] security: [] tags: - name: host description: The host process itself — version, uptime, mode, store. - name: sessions description: Durable conversation containers. Archive, never destroy. - name: messages description: Submitting work into a session and interrupting it. - name: events description: The server-sent event stream every client consumes. - name: lanes description: Parallel tracks inside a session — main, subagent, side. - name: agents description: Named recipes — instructions, tools, model, policy. Read-only in v1. - name: ladder description: >- What a person can type: the skills and command files in force for one repository, and expanding one into text. Five origins merged, nearest winning a name, the repository's own rungs gated on trust. - name: permissions description: Pending permission asks, decisions, and the decision audit. - name: intercom description: Sessions on one machine finding and messaging each other. - name: packages description: The one thing a user installs — resources, Go code, or both. - name: workflows description: Deterministic multi-agent orchestration runs. - name: providers description: Model suppliers, their auth state, and the model catalogue. - name: monitors description: >- Long-running watchers a session keeps beside its conversation — a test runner in watch mode, a build, a log being followed. Started by the model or by the person, always listed, always killable. - name: records description: The queryable local record of everything that happened. - name: schedules description: >- Work the host's own clock starts with nobody present — a repository, a prompt, a rule and what one fire may spend. Cancel, never destroy. paths: /v1/sessions/{sessionId}/changes: parameters: - $ref: '#/components/parameters/SessionIdParam' get: tags: - sessions summary: Read what a session changed on disk description: >- The files this session's write, edit and delete tools changed, each with what it did to the file, how many lines moved, and the content the file held before the session first touched it. It is what a diff view of a session's own work stands on, and what a touched-files list shows counts from. Every row is measured from FIRST touch. A file the session edited five times is one row comparing what it held before edit one against what is on disk now — not five rows, and not the last edit's delta. That is also why a file put back the way it was is absent from the answer: it changed nothing, and reporting it at zero lines either way would claim otherwise. The current content is deliberately not served. The host and its clients share a filesystem, so a client reads the file itself and gets the version it is about to let somebody edit, rather than a copy that was already stale when it was sent. What only the host has is the before side. Both sides are bounded at 1 MiB (1048576 bytes). Past that nothing was kept, and the row says so through beforeState rather than serving an empty file or a truncated one: beforeBytes still carries the real size, so a client can say how large the file it cannot diff is. linesAdded and linesRemoved are then absent, because a count nobody could compute is not zero. operationId: listSessionChanges parameters: - name: path in: query required: false description: >- Filter to one file, by the absolute path this operation reports for it, and serve that file's before content. Without it the answer covers every file the session changed and carries no content at all — a change list stays cheap, and the one file a diff view is opening is the one it asks for. A path this session never changed is an empty answer, not an error. schema: type: string maxLength: 4096 - name: entryId in: query required: false description: >- Answer for ONE step of the conversation instead of for the session: what the tool call recorded on this entry did to each file it mutated, measured from the restore point taken before that entry to the one taken at it. Both sides are then served (beforeContent and afterContent), because the after side is a moment that has since been edited over and nothing on disk remembers it. It exists because the session-scoped answer above is the wrong one under an old receipt: a file edited five times has one row carrying all five edits, so drawing it under the first receipt credits that call with every line that came after it. An entry whose step mutated nothing is an empty answer, not an error, and a step the host never snapshotted comes back with beforeState "too-large" — nothing was kept — rather than as an empty diff. path and entryId are not combined; entryId wins when both are given. schema: type: string format: uuid responses: '200': description: The files this session changed. content: application/json: schema: $ref: '#/components/schemas/FileChangeSet' '400': $ref: '#/components/responses/BadRequest' '404': $ref: '#/components/responses/NotFound' '500': $ref: '#/components/responses/InternalServerError' components: parameters: SessionIdParam: name: sessionId in: path required: true description: The session's id. schema: type: string format: uuid schemas: FileChangeSet: type: object description: >- Every file a session changed, in the order the session first met them. Not paginated: the set is bounded by what one conversation's tools actually mutated, and a client that wants one file asks for it by path. required: - items properties: items: type: array items: $ref: '#/components/schemas/FileChange' examples: - items: - path: /home/dev/ledger/validate.go op: modified beforeState: text beforeBytes: 4211 linesAdded: 12 linesRemoved: 3 FileChange: type: object description: >- One file a session changed, measured from the content it held when the session first touched it to what is on disk now. required: - path - op - beforeState - beforeBytes properties: path: type: string description: The file's absolute path. op: type: string enum: - added - modified - deleted - renamed x-enum-varnames: - FileChangeOpAdded - FileChangeOpModified - FileChangeOpDeleted - FileChangeOpRenamed description: >- What the session did to the file, at file granularity: it was not there and now is, it was there and changed, it was there and is gone, or it is the same bytes under another name. This is the file-level fact a change list shows, not the per-call read/write/edit a tool receipt carries. renamed is reported only where it can be known for certain and costs nothing to know: inside one change set, a file that went and a file that arrived whose content is byte-identical are one row naming both paths, and previousPath carries the name it had. There is no rename DETECTION behind this — no git, no similarity score — so a file that was moved AND edited is still reported as an added row beside a deleted one, which is what a reader without this value gets for every move. A client that does not know the value degrades to whatever it draws for an op it cannot name. beforeState: type: string enum: - absent - text - not-text - too-large x-enum-varnames: - FileChangeBeforeStateAbsent - FileChangeBeforeStateText - FileChangeBeforeStateNotText - FileChangeBeforeStateTooLarge description: >- What is known about the content the file held before the session changed it, so an unavailable diff is never mistaken for an empty one. absent — the file did not exist, and the whole of it is added. text — beforeContent carries it when this read asked about a single path. not-text — the bytes were kept but are not valid UTF-8, so they are never served as a string and no line count over them would mean anything. too-large — the file was past the 1 MiB bound and nothing was kept; beforeBytes says how large it was. beforeBytes: type: integer format: int64 minimum: 0 description: >- The file's size when the session first touched it, 0 when it did not exist. True even when the content itself was too large to keep. beforeContent: type: string description: >- The content the file held before the session changed it. Present only when the request named a single path or one entry AND beforeState is text or absent — a file the step created has no before side, so absent pairs with the empty string here, which is the side a created file is diffed against. A client diffs it against the file it reads from disk itself, and edits the second side. afterContent: type: string description: >- The other side, present only on an entryId read. A session-scoped change is measured against the file on disk, which the client shares and reads itself; one step's change ends at a moment that has since been edited over, so the host serves both ends or the diff cannot be drawn at all. linesAdded: type: integer minimum: 0 description: >- Lines this session added, counted from the before content against the file as it is now. Absent when no diff could be computed — see beforeState — because a count nobody could compute is not zero. linesRemoved: type: integer minimum: 0 description: Lines this session removed, on the same terms as linesAdded. previousPath: type: string description: >- The absolute path the file had before the session moved it, on a renamed row and nowhere else. path is where the file is now, so a reader states the move from the two together. The row's before side — beforeState, beforeBytes, beforeContent — belongs to this path, since that is the file the content was measured from. examples: - path: /home/dev/ledger/validate.go op: modified beforeState: text beforeBytes: 4211 beforeContent: | package ledger linesAdded: 12 linesRemoved: 3 Error: type: object description: >- The single error envelope every operation returns. Codes are NRY- followed by four digits and are catalogued in the top-level x-error-catalog extension. fields appears only on 422 validation errors, mapping each offending property to its problem. required: - code - title - message properties: code: type: string pattern: ^NRY-[0-9]{4}$ description: Machine-readable error code from the NRY catalogue. title: type: string maxLength: 256 description: Short human-readable summary of the error class. message: type: string maxLength: 4096 description: Specific, actionable description of what went wrong. fields: type: object description: Per-field validation problems. Present on 422 only. additionalProperties: type: string examples: - code: NRY-0002 title: Session not found message: >- No session with id 6b9f6d2e-1c3a-4f5b-9d7e-2a8c4e6f0b1d exists on this host. responses: BadRequest: description: Malformed request — invalid parameter, cursor, or JSON body. content: application/json: schema: $ref: '#/components/schemas/Error' NotFound: description: The addressed resource does not exist on this host. content: application/json: schema: $ref: '#/components/schemas/Error' InternalServerError: description: The host failed — including a store that refuses writes (NRY-0012). content: application/json: schema: $ref: '#/components/schemas/Error' ````