docs(burst): update docs site and add burst example config

README.md

@@ -186,6 +186,7 @@ sendit completion <shell>
 | `--log-level` | | *(from config)* | Override log level: `debug` \| `info` \| `warn` \| `error` |
 | `--dry-run` | | `false` | Print config summary (targets, pacing, limits) and exit without sending traffic |
 | `--capture` | | `""` | Write a synthetic PCAP file while running; file is finalised on clean shutdown |
+| `--duration` | | *(unlimited)* | Auto-stop after this wall-clock time (e.g. `5m`, `30s`); **required** when `pacing.mode: burst` |
 
 ### `probe` flags
 
@@ -569,18 +570,20 @@ Controls how requests are spaced in time.
 
 | Field | Default | Description |
 |-------|---------|-------------|
-| `mode` | `human` | `human` \| `rate_limited` \| `scheduled` |
+| `mode` | `human` | `human` \| `rate_limited` \| `scheduled` \| `burst` |
 | `requests_per_minute` | `20` | Target RPM — used by `rate_limited` and `scheduled` modes only |
 | `jitter_factor` | `0.4` | Unused in `human` mode; reserved for future modes |
 | `min_delay_ms` | `800` | Minimum inter-request delay in `human` mode |
 | `max_delay_ms` | `8000` | Maximum inter-request delay in `human` mode |
 | `schedule` | `[]` | List of cron windows — required when `mode: scheduled` |
+| `ramp_up_s` | `0` | Seconds to linearly ramp up to full speed — `burst` mode only; `0` = immediate |
 
 **Pacing modes:**
 
 - **`human`** — random delay per request uniformly sampled from `[min_delay_ms, max_delay_ms]`. `requests_per_minute` and `jitter_factor` are ignored in this mode.
 - **`rate_limited`** — token-bucket limiter at `requests_per_minute` plus a small random jitter after each token.
 - **`scheduled`** — cron expressions open active windows; within each window behaves like `rate_limited` at the window's own RPM. Dispatch is paused between windows.
+- **`burst`** — fires requests as fast as worker slots allow with no inter-request delay. Intended for internal infrastructure testing. **Requires `--duration`** on `sendit start` — the engine refuses to run an unbounded burst session.
 
 ```yaml
 pacing:
@@ -591,6 +594,13 @@ pacing:
       requests_per_minute: 40
 ```
 
+```yaml
+# Burst example — always pair with --duration when starting
+pacing:
+  mode: burst
+  ramp_up_s: 30   # optional: ramp from slow to full speed over 30 s
+```
+
 ### `limits`
 
 Concurrency and resource thresholds.

config/burst.yaml

@@ -0,0 +1,76 @@
+# burst.yaml — example configuration for burst / load-test mode
+#
+# Burst mode fires at full worker concurrency with no inter-request delay.
+# It is designed for internal load testing and staging validation, not for
+# traffic to third-party services.
+#
+# REQUIRED: --duration must be set on the command line when pacing.mode is burst.
+#
+#   sendit start --config config/burst.yaml --duration 2m
+#
+# The optional ramp_up_s field linearly increases from a throttled start to
+# full speed over the specified number of seconds. This prevents a thundering
+# herd on startup. Delay per request = 50ms × remaining_ramp_up_seconds,
+# capped at 5 s.
+
+pacing:
+  mode: burst
+  ramp_up_s: 30         # ramp from ~1500 ms/req to zero over 30 s
+
+limits:
+  max_workers: 20
+  max_browser_workers: 2
+  cpu_threshold_pct: 80.0
+  memory_threshold_mb: 2048
+
+# Rate limits and backoff are intentionally relaxed for burst mode.
+# The engine still respects them — remove or adjust as needed.
+rate_limits:
+  default_rps: 50.0
+
+backoff:
+  initial_ms: 500
+  max_ms: 10000
+  multiplier: 2.0
+  max_attempts: 2
+
+targets:
+  - url: "http://localhost:8080/health"
+    weight: 5
+    type: http
+    http:
+      method: GET
+      timeout_s: 5
+
+  - url: "http://localhost:8080/api/v1/status"
+    weight: 3
+    type: http
+    http:
+      method: GET
+      headers:
+        Accept: "application/json"
+      timeout_s: 5
+
+  - url: "http://localhost:8080/api/v1/submit"
+    weight: 2
+    type: http
+    http:
+      method: POST
+      headers:
+        Content-Type: "application/json"
+      body: '{"probe":true}'
+      timeout_s: 10
+
+output:
+  enabled: true
+  file: "burst-results.jsonl"
+  format: jsonl
+  append: false
+
+metrics:
+  enabled: true
+  prometheus_port: 9090
+
+daemon:
+  log_level: info
+  log_format: text

config/example.yaml

@@ -1,5 +1,5 @@
 pacing:
-  mode: human                   # human | rate_limited | scheduled
+  mode: human                   # human | rate_limited | scheduled | burst
   requests_per_minute: 20
   jitter_factor: 0.4
   min_delay_ms: 800
@@ -9,6 +9,8 @@ pacing:
     - cron: "0 9 * * 1-5"       # weekdays at 09:00
       duration_minutes: 30
       requests_per_minute: 40
+  # ramp_up_s is only used when mode: burst
+  # ramp_up_s: 30               # linearly ramp up over 30 s; 0 = immediate full speed
 
 limits:
   max_workers: 4

docs/content/docs/configuration.md

@@ -15,12 +15,13 @@ Controls how requests are spaced in time. See [Pacing Modes](../pacing/) for det
 
 | Field | Type | Default | Description |
 |---|---|---|---|
-| `mode` | string | `human` | `human` \| `rate_limited` \| `scheduled` |
+| `mode` | string | `human` | `human` \| `rate_limited` \| `scheduled` \| `burst` |
 | `requests_per_minute` | float | `20` | Target RPM — used by `rate_limited` and `scheduled` only |
 | `jitter_factor` | float | `0.4` | Reserved for future modes; unused in current pacing logic |
 | `min_delay_ms` | int | `800` | Minimum inter-request delay for `human` mode (ms) |
 | `max_delay_ms` | int | `8000` | Maximum inter-request delay for `human` mode (ms) |
 | `schedule` | list | `[]` | Cron windows — required when `mode: scheduled` |
+| `ramp_up_s` | int | `0` | Seconds to linearly ramp up to full speed — `burst` mode only; `0` = immediate full speed |
 
 ## `limits`