diff --git a/mxaccesscli/README.md b/mxaccesscli/README.md
index 77fc09b..26164ef 100644
--- a/mxaccesscli/README.md
+++ b/mxaccesscli/README.md
@@ -64,6 +64,15 @@ dotnet run --project src/MxAccess.Cli/MxAccess.Cli.csproj -- write TestMachine_0
# Subscribe to a tag for 30 seconds, JSON Lines for streaming:
dotnet run --project src/MxAccess.Cli/MxAccess.Cli.csproj -- subscribe TestMachine_001.Speed -s 30 --llm-json
+
+# Batch read from a JSONL file (one tag string or {"tag":"..."} per line):
+mxa read-batch tags.jsonl --llm-json
+
+# Batch write {tag,value,type?} pairs piped from stdin:
+echo '{"tag":"TM.Setpoint","value":42.5,"type":"double"}' | mxa write-batch - --llm-json
+
+# Batch subscribe from a JSONL file, streaming for 30s:
+mxa subscribe-batch tags.jsonl -s 30 --llm-json
```
The built executable is `bin\x86\Release\net48\mxa.exe`. Drop on `PATH` and use `mxa read ...`.
diff --git a/mxaccesscli/docs/usage.md b/mxaccesscli/docs/usage.md
index 8d603c4..237af63 100644
--- a/mxaccesscli/docs/usage.md
+++ b/mxaccesscli/docs/usage.md
@@ -11,6 +11,42 @@ Read, write, and subscribe to AVEVA System Platform tags via MxAccess. The CLI r
- **Subsequent events are fast.** Once a tag is bound, value-change updates propagate within ~100 ms.
- **Exit codes:** `0` on success, `1` if any operation timed out or returned a non-Ok / non-Pending `MxStatusCategory`, `2` on argument-validation errors.
+## Batch input format
+
+The three `-batch` commands (`read-batch`, `write-batch`, `subscribe-batch`) all
+take a single positional `` argument which is either a path to a JSONL
+file or `-` to read JSONL from stdin. The line conventions are shared:
+
+- **Blank lines and lines starting with `#`** are skipped. Line numbers still
+ count them, so error messages stay accurate against the source file.
+- **Per-line auth override is not supported in v1.** All entries in a
+ `write-batch` use the same `--username` / `--password` / `--user-id` /
+ `--secured` / `--verifier-*` flags supplied on the command line.
+- **Duplicate tags are allowed.** Each input line is an independent entry
+ with its own item handle and its own row in `results[]`.
+
+Read / subscribe lines accept **either** a bare JSON string or an object form:
+
+```jsonl
+"TestMachine_001.Speed"
+{"tag": "Reactor1.Level"}
+```
+
+Write lines are object form only:
+
+```jsonl
+{"tag": "TM.Setpoint", "value": 42.5, "type": "double"}
+{"tag": "TM.RunFlag", "value": true}
+{"tag": "TM.Parts[]", "value": ["", "11111", ""], "type": "string"}
+```
+
+`value` may be a JSON `bool`, `number`, `string`, or `array`. A JSON array
+requires the tag to end in `[]` (whole-array reference, matches the `mxa write`
+rule). `type` is optional; when omitted the JSON token's native type drives the
+default. When set, `type` accepts the same vocabulary as `mxa write --type`
+(`bool`, `byte`, `short`, `int`, `long`, `float`, `double`, `string`,
+`datetime`).
+
## `mxa info`
Print the loaded `ArchestrA.MxAccess` assembly identity, supported `--type` values, and the full `MxStatusCategory` enum. No tag access.
@@ -193,6 +229,188 @@ LLM-JSON output (one event per line, no surrounding `[ ... ]`):
JSON Lines lets a downstream consumer parse events incrementally rather than buffering the whole stream — the right shape for indefinite or long-running subscriptions.
+## `mxa read-batch `
+
+Reads many tags from a JSONL file (or `-` for stdin) in **one** MxSession,
+amortizing the 3–8 s LMX bind cost across the whole batch. Line shape is
+defined in [Batch input format](#batch-input-format). Result rows arrive in
+input-line order regardless of which `OnDataChange` fires first.
+
+| Option | Default | Notes |
+| --- | --- | --- |
+| `-t`, `--timeout ` | `5` | Wall budget for the whole batch (not per-tag). Tags that haven't delivered a `DataChange` by the deadline are reported with `error: "timeout"`. |
+| `--client ` | `mxa` | Passed to `Register()`. |
+| `--llm-json` | off | Emit the JSON envelope. |
+
+Example:
+
+```powershell
+mxa read-batch tags.jsonl --llm-json
+echo '"TM.Speed"' | mxa read-batch - --llm-json
+```
+
+LLM-JSON envelope (one results row per non-blank input line, carrying the
+1-based `line` for traceability):
+
+```json
+{
+ "query": { "command": "read-batch", "input": "tags.jsonl", "timeout_s": 5.0, "client": "mxa" },
+ "ok": true,
+ "results": [
+ { "tag": "TM.Speed", "line": 1, "ok": true, "value": 1234.5, "quality": 192, "timestamp": "...", "statuses": [...] },
+ { "tag": "Reactor1.Level","line": 2, "ok": true, "value": 78.1, "quality": 192, "timestamp": "...", "statuses": [...] }
+ ]
+}
+```
+
+Exit code: `0` if every entry resolved Ok; `1` if any timed out or returned a
+non-Ok status; `2` for parse errors, missing input, or empty input.
+
+## `mxa write-batch `
+
+Writes many tag/value pairs from a JSONL file (or `-`) in **one** MxSession,
+**pipelining** per-item resolve and write so wall time is roughly
+`max(resolve_latency) + max(write_ack)` instead of `N × (resolve_latency +
+write_ack)`. Auth is resolved once before any item is touched.
+
+Line shape: see [Batch input format](#batch-input-format). Auth flags follow
+the same semantics as `mxa write` — see [Authentication](#authentication) for
+how `--username` / `--domain` / `--secured` / `--verifier-*` interact. Per-line
+auth override is **out of scope for v1** (planned follow-up).
+
+| Option | Default | Notes |
+| --- | --- | --- |
+| `-t`, `--timeout ` | `5` | Per-phase wall budget. Phase A (resolve types) and Phase B (await `OnWriteComplete`) each get this many seconds. |
+| `--user-id ` | `0` | Pre-resolved authenticated user id. See `mxa write` for caveats. |
+| `-u`, `--username ` | (none) | Galaxy / OS username. Resolved to a userId via `AuthenticateUser` once before Phase A. |
+| `--domain ` | (none) | Combined with `--username` as `\`. |
+| `-p`, `--password ` | (none) | Password for `--username`. Redacted in the LLM-JSON `query` echo. |
+| `--secured` | off | Route writes through `WriteSecured(currentUserId, verifierUserId, value)`. Required for Secured Write / Verified Write classifications. |
+| `--verifier-username` / `--verifier-domain` / `--verifier-password` | (none) | Two-person verified write; implies `--secured`. |
+| `--client ` | `mxa` | Passed to `Register()`. |
+| `--llm-json` | off | Emit the JSON envelope. |
+
+Example:
+
+```powershell
+# Set up Hi/HiHi/Lo/LoLo limits and enable alarms for a tag in one shot:
+mxa write-batch limits.jsonl --llm-json
+```
+
+```jsonl
+{"tag":"BCD_T1.HighLimit", "value": 80, "type": "float"}
+{"tag":"BCD_T1.HighHighLimit", "value": 95, "type": "float"}
+{"tag":"BCD_T1.LowLimit", "value": 20, "type": "float"}
+{"tag":"BCD_T1.LowLowLimit", "value": 5, "type": "float"}
+{"tag":"BCD_T1.HighAlarm.Alarmed", "value": true}
+{"tag":"BCD_T1.HighHighAlarm.Alarmed", "value": true}
+{"tag":"BCD_T1.LowAlarm.Alarmed", "value": true}
+{"tag":"BCD_T1.LowLowAlarm.Alarmed", "value": true}
+```
+
+LLM-JSON envelope (per-entry row with auth attribution and `line` echo):
+
+```json
+{
+ "query": { "command": "write-batch", "input": "limits.jsonl", "entries": 8,
+ "timeout_s": 5.0, "user_id": 0, "verify_user": null, "secured": false, "client": "mxa" },
+ "ok": true,
+ "results": [
+ { "tag": "BCD_T1.HighLimit", "line": 1, "ok": true, "error": null,
+ "authenticated": false, "auth_user_id": null, "secured": false,
+ "verifier_user_id": null, "statuses": [...] }
+ ]
+}
+```
+
+### Failure modes — `write-batch`
+
+| `error` string | Cause | Exit |
+| --- | --- | --- |
+| (top-level) `parse-error` | One or more lines failed JSONL / schema validation; `results[]` lists each. | 2 |
+| (top-level) `empty-input` | File / stdin contained no non-blank entries. | 2 |
+| (top-level) `authentication-failed` | `AuthenticateUser` returned 0 for the operator credentials. **No items attempted.** | 1 |
+| (top-level) `verifier-authentication-failed` | Same for the verifier in two-person Verified Write. | 1 |
+| per-entry `add-item-failed: …` | `LMXProxyServer.AddItem` threw (typically a malformed reference). | 1 |
+| per-entry `timeout-resolving-type` | No `OnDataChange` arrived for this item before `--timeout` elapsed. | 1 |
+| per-entry `type-resolution-failed` | First `OnDataChange` carried a non-Ok status — `statuses` filled. | 1 |
+| per-entry `value-coerce-failed: …` | JSON value couldn't be converted to the configured `--type` (or inferred type). The Write was **not** queued. | 1 |
+| per-entry `write-call-failed: …` | The `Write` / `WriteSecured` COM call itself threw before `OnWriteComplete`. | 1 |
+| per-entry `timeout` | No `OnWriteComplete` arrived before `--timeout` elapsed. | 1 |
+| per-entry `write-failed` | `OnWriteComplete` arrived with non-Ok statuses (e.g. read-only attr, security denied). | 1 |
+
+The process exits `1` if any per-entry row failed, `0` if every row was Ok.
+The envelope's top-level `ok` matches.
+
+## `mxa subscribe-batch `
+
+Subscribes to many tags from a JSONL file (or `-`) and streams `OnDataChange`
+events for a duration. The streaming output is identical to `mxa subscribe` —
+no envelope wrap; one event per line when `--llm-json` is set.
+
+Line shape: see [Batch input format](#batch-input-format).
+
+| Option | Default | Notes |
+| --- | --- | --- |
+| `-s`, `--seconds ` | `10` | Wall-clock duration of the subscription. |
+| `--max ` | `1000` | Hard cap on emitted events. |
+| `--client ` | `mxa` | Passed to `Register()`. |
+| `--llm-json` | off | JSON Lines mode — one event per line, no outer envelope. |
+
+First-event latency is still 3–8 s per tag, but `Advise()` is issued for every
+tag up front so the binds run in parallel — wall time matches a single-tag
+subscribe. For short `--seconds` windows (< 5 s) you may miss the initial
+values; budget accordingly.
+
+Example:
+
+```powershell
+mxa subscribe-batch tags.jsonl -s 30 --llm-json
+```
+
+Output stream (each event as one JSON line):
+
+```jsonl
+{"tag":"TM.Speed","ok":true,"value":1234.5,"quality":192,"timestamp":"...","statuses":[...]}
+{"tag":"Reactor1.Level","ok":true,"value":78.1,"quality":192,"timestamp":"...","statuses":[...]}
+```
+
+Exit code: `0` on a clean run, `1` if every tag failed to subscribe (no item
+ever bound), `2` for parse errors / missing input / empty input.
+
+## Batch commands — verified live
+
+Captured on 2026-05-10 against the dev `ZB` galaxy (System Platform 2017
+Express, MxAccess `3.2.0.0`). The galaxy is configured permissively
+(`eNone` / Free Access) so writes were issued anonymously.
+
+| Scenario | Result |
+| --- | --- |
+| `read-batch` 3 entries (bare-string + object + duplicate, with blank/`#` lines) | All three returned in input-line order; `line` field correctly reflected `1, 2, 5`. |
+| `read-batch` continue-on-error (`NoSuchObject.NoSuchAttribute` mixed with `DevPlatform.CPULoad`) | Good entry returned value, bad entry returned `Category=MxCategoryConfigurationError, Detail=6`. Exit 1. |
+| `write-batch` 5 entries (1 attribute with `security_classification=5` failed `SecurityError, Detail=1007`; rest wrote anonymously) | 4/5 wrote; per-item statuses preserved; exit 1. Round-trip read confirmed `TuneValue=7.25`, `ProtectedValue=true`, `ProtectedValue1=false`, `MoveInPartNumbers[1]="PN-42"`. |
+| `write-batch` failure-mode coverage (`value-coerce-failed` + `type-resolution-failed` + ok, same `TuneValue` tag duplicated) | Each failure surfaced its distinct `error` string; duplicate tag entries are independent handles. |
+| `subscribe-batch` two tags, 18-second window | Both tags bound in parallel; CPULoad streamed ~26 `OnDataChange` events; `SystemStartupTime` delivered its initial value then stayed quiet (constant). Exit 0. |
+| Parse error on stdin (`{ malformed json }`) | `results[]` row with `error: "parse-error"`, line + reason, no LMX session opened. Exit 2. |
+| Missing input file | Top-level `error` envelope, exit 2. |
+
+### Pipelining timing
+
+Same four writes (`OtOpcUaParityTest_001.TuneValue`,
+`TestMachine_001.ProtectedValue`, `TestMachine_001.ProtectedValue1`,
+`MESReceiver_001.MoveInPartNumbers[1]`) executed two ways, wall-clock:
+
+| Method | Wall time | Notes |
+| --- | --- | --- |
+| 4 × `mxa write` (sequential subprocess invocations) | **38.2 s** | Each invocation pays the 3–8 s LMX bind once. |
+| 1 × `mxa write-batch` (4 writes in one MxSession, two-phase pipeline) | **10.3 s** | Includes a 5th entry that failed `SecurityError` — still resolved in Phase A. |
+
+≈ **3.7× faster** at N=4. The cost model is roughly `~max(resolve_latency)
++ ~max(write_ack)` for the batched form versus `N × (resolve_latency +
+write_ack)` for the sequential form, so the speedup grows with N: at ~10
+writes the savings are typically 60–80 seconds, which is the scale of the
+test-plan setup phases this command was added for.
+
## Type support matrix
Verified end-to-end against the live `ZB` galaxy (System Platform 2017 Express, MxAccess `3.2.0.0`). Each row records what the wire shape looks like in the JSON envelope.
diff --git a/mxaccesscli/src/MxAccess.Cli/Commands/ReadBatchCommand.cs b/mxaccesscli/src/MxAccess.Cli/Commands/ReadBatchCommand.cs
new file mode 100644
index 0000000..9ee774d
--- /dev/null
+++ b/mxaccesscli/src/MxAccess.Cli/Commands/ReadBatchCommand.cs
@@ -0,0 +1,227 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using CliFx;
+using CliFx.Attributes;
+using CliFx.Exceptions;
+using CliFx.Infrastructure;
+using MxAccess.Cli.Mx;
+using MxAccess.Cli.Output;
+
+namespace MxAccess.Cli.Commands
+{
+ [Command("read-batch", Description =
+ "Read many tags from a JSONL input file (or stdin via '-'). One MxSession " +
+ "amortizes the LMX bind cost across the whole batch.")]
+ public sealed class ReadBatchCommand : ICommand
+ {
+ [CommandParameter(0, Name = "input",
+ Description = "Path to a JSONL file. Use '-' to read JSONL from stdin. " +
+ "Each line is either a bare tag string (e.g. \"TM.Speed\") or " +
+ "an object (e.g. {\"tag\":\"TM.Speed\"}). Blank and '#'-prefixed lines are skipped.")]
+ public string Input { get; init; }
+
+ [CommandOption("timeout", 't', Description = "Per-tag timeout in seconds while waiting for the first value. Default 5.")]
+ public double TimeoutSeconds { get; init; } = 5.0;
+
+ [CommandOption("client", Description = "MxAccess client name passed to Register(). Default 'mxa'.")]
+ public string ClientName { get; init; } = "mxa";
+
+ [CommandOption("llm-json", Description = "Emit the JSON envelope { query, ok, results } instead of human-readable lines.")]
+ public bool LlmJson { get; init; }
+
+ public ValueTask ExecuteAsync(IConsole console)
+ {
+ if (string.IsNullOrWhiteSpace(Input))
+ throw new CommandException("Input path is required (use '-' for stdin).", 2);
+ if (TimeoutSeconds <= 0)
+ throw new CommandException("--timeout must be positive.", 2);
+
+ var query = new
+ {
+ command = "read-batch",
+ input = Input,
+ timeout_s = TimeoutSeconds,
+ client = ClientName,
+ };
+
+ // Phase 1: load + parse. Collect all parse errors so the user gets
+ // every malformed line in one report instead of fixing them one at
+ // a time.
+ var entries = new List();
+ var parseErrors = new List