> ## 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. # Report every declared external tool server's health and cost > Answers, per declared MCP tool server, whether it is up, since when, how many consecutive connection attempts have failed and why the last one did — plus how many calls it has been asked to make and how many characters of model context its presence in the budgeted catalogue spends. Health is taken live off an MCP ping while answering, so a server holding an open socket and answering nothing reads as down rather than as connected. The whole sweep is bounded by the request: the pings go out in parallel, so eight silent endpoints cost one ping ceiling between them. ## OpenAPI ````yaml /en/openapi/v3-current/narya.yaml get /v1/tool-servers 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/tool-servers: get: tags: - host summary: Report every declared external tool server's health and cost description: >- Answers, per declared MCP tool server, whether it is up, since when, how many consecutive connection attempts have failed and why the last one did — plus how many calls it has been asked to make and how many characters of model context its presence in the budgeted catalogue spends. Health is taken live off an MCP ping while answering, so a server holding an open socket and answering nothing reads as down rather than as connected. The whole sweep is bounded by the request: the pings go out in parallel, so eight silent endpoints cost one ping ceiling between them. operationId: listToolServers responses: '200': description: One entry per declared tool server, in name order. content: application/json: schema: type: array items: $ref: '#/components/schemas/ToolServerHealth' '500': $ref: '#/components/responses/InternalServerError' components: schemas: ToolServerHealth: type: object description: >- One external tool server's health and cost. tools is how many of its tools are in the registry right now — a server that went down has none, because its tools leave the registry rather than erroring on call. required: - name - status - tools - attempts - calls - catalogueBytes properties: name: type: string description: The name the server was declared under. status: type: string description: >- waiting-for-sign-in is a connection attempt held open for a PERSON: the server demanded OAuth, the host put an authorization URL in front of whoever is watching, and nothing else is wrong. It is reported separately from connecting because the two need opposite reactions — connecting resolves itself, this one resolves only when somebody opens signInUrl — and because the alternative was a five-minute "connecting" whose eventual failure read "context canceled" and never named the sign-in. enum: - connecting - connected - down - waiting-for-sign-in since: type: string format: date-time description: >- When the server entered this status — for waiting-for-sign-in, when the host started waiting on the person. tools: type: integer minimum: 0 attempts: type: integer minimum: 0 description: Consecutive failures since this server last connected. calls: type: integer format: int64 minimum: 0 description: Tool calls this server has been asked to make. catalogueBytes: type: integer minimum: 0 description: Characters of model context this server's catalogue entry spends. pingMs: type: integer minimum: 0 description: >- Round trip of the live MCP ping taken while answering. Absent when the server is not connected, or when the ping failed — in which case lastError says so. lastError: type: string description: Why the last attempt, session or ping failed. signInUrl: type: string description: >- The authorization page a person must open to finish this server's sign-in. Present only while status is waiting-for-sign-in. signInExpiresAt: type: string format: date-time description: >- When this sign-in window closes. Present only while status is waiting-for-sign-in. examples: - name: matcher status: down since: '2026-08-13T09:12:00.000Z' tools: 0 attempts: 14 calls: 0 catalogueBytes: 0 lastError: 'connect: executable file not found in $PATH' Error: type: object description: >- The single error envelope every operation returns. Codes are NRY- followed by four digits and are catalogued in the top-level x-error-catalog extension. fields appears only on 422 validation errors, mapping each offending property to its problem. required: - code - title - message properties: code: type: string pattern: ^NRY-[0-9]{4}$ 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: InternalServerError: description: The host failed — including a store that refuses writes (NRY-0012). content: application/json: schema: $ref: '#/components/schemas/Error' ````