xwave

name	xwave
description	Use when an AI agent needs structured JSON access to FSDB waveform facts through xwave, including sessions, scope discovery, values, signal lists, APB/AXI transactions, generic events, condition checks, expression/window verification, signal inspection, anomaly detection, handshake inspection, or protocol debug facts.

xwave AI JSON Interface

This skill is for AI agents using xwave ai ... as a structured waveform fact API. Prefer the AI JSON entry point over the human CLI whenever you need machine-readable output, deterministic errors, or multi-step debug evidence.

Human-oriented legacy CLI details were moved to references/cli-reference.md. Load that file only when the user explicitly asks about non-AI command syntax.

Entry Point

Use one of these forms:

tools/xwave-env ai query request.json
tools/xwave-env ai query -
tools/xwave-env ai query --json '{"api_version":"xwave.ai.v1","action":"value.at","target":{"fsdb":"waves.fsdb","auto_open":true},"args":{"signal":"top.clk","time":"10ns"}}'
tools/xwave-env ai query --json '{"api_version":"xwave.ai.v1","action":"cursor.set","target":{"session_id":"case_a"},"args":{"name":"deadlock","time":"120340ns","note":"stall start"}}'
tools/xwave-env ai query --json '{"api_version":"xwave.ai.v1","action":"value.at","target":{"session_id":"case_a"},"args":{"signal":"top.ready","at":"@deadlock-20ns","format":"hex"}}'
tools/xwave-env ai schema
tools/xwave-env ai actions

Output Verbosity

Important: xwave ai query defaults to compact output. Compact output deliberately omits tool, session, empty warnings, empty suggested_next_actions, and meta.elapsed_ms. Do not assume those fields exist unless you request them.

Use compact for normal AI workflows:

{"output":{"verbosity":"compact"}}

Use full when maintaining older scripts or discovering exact response fields:

{"output":{"verbosity":"full"}}

Use debug when diagnosing session/daemon/socket/FSDB fingerprint issues:

{"output":{"verbosity":"debug"}}

Errors still include structured error.code/message, and non-empty recovery hints remain present in compact output.

AI value objects are intentionally minimal everywhere: {"value":"...", "known":true|false}. Do not expect text, bits, hex, unsigned, signed, or unknown_reason; choose the string representation with request format.

For scripted extraction, pipe JSON output into python3 instead of parsing human text. This is the recommended way for AI agents to pull specific fields or compute custom statistics:

tools/xwave-env ai query --json '{"api_version":"xwave.ai.v1","action":"session.list"}' \
  | python3 -c 'import json,sys; d=json.load(sys.stdin); print(d["ok"], d.get("summary", {}))'

For larger summaries, keep the xwave query bounded and do the aggregation in Python:

tools/xwave-env ai query --json '{"api_version":"xwave.ai.v1","action":"event.export","target":{"session_id":"case_a"},"args":{"name":"if0","expr":"valid && !ready","time_range":{"begin":"0ns","end":"100us"}},"limits":{"max_rows":1000}}' \
  | python3 -c 'import json,sys; d=json.load(sys.stdin); rows=d.get("data",{}).get("events",[]); print(len(rows))'

For event counts or grouped counts, prefer built-in aggregation over exporting all rows:

tools/xwave-env ai query --json '{"api_version":"xwave.ai.v1","action":"event.export","target":{"session_id":"case_a"},"args":{"name":"if0","expr":"valid && ready","time_range":{"begin":"0ns","end":"100us"},"aggregate":{"count":true,"group_by":["qid"],"events":false}}}'

Request envelope:

{
  "api_version": "xwave.ai.v1",
  "request_id": "optional-id",
  "action": "value.at",
  "target": {
    "fsdb": "/path/to/waves.fsdb",
    "auto_open": true
  },
  "args": {},
  "limits": {
    "max_rows": 1000,
    "max_events": 1000,
    "max_samples": 1000000
  },
  "output": {
    "verbosity": "compact"
  }
}

Response envelope always contains:

compact: ok/action plus non-empty summary/data/findings/error/suggested_next_actions/meta.truncated
full/debug: ok/action/session/summary/data/findings/suggested_next_actions/warnings/error/meta

Only ok/action/error and action-specific key data should be treated as always relevant. Field presence depends on output.verbosity; compact output will not include session/meta/tool scaffolding. Field names inside summary, data, and findings are action-specific and may differ by action. Do not guess detailed keys such as latency subfields from memory. For a field dictionary and extraction guidance, see references/ai-response-dictionary.md. For exact fields on a specific build and FSDB, run tools/xwave-env ai schema when available, or issue a small bounded query and inspect the returned JSON before writing extraction code.

AI usage rules:

• Start with session.open for repeated work, then use target.session_id as a string.
• For one-shot queries, use target.fsdb + auto_open:true.
• Always inspect ok and error.code; do not parse human text.
• Prefer python3 -c 'import json,sys; ...' pipelines for extracting fields or computing statistics from xwave ai query output.
• Use cursor.set after finding an important event time, then use @name, @name-20ns, @name+5ns, @name-10cycle(top.clk), or active cursor forms such as @-10ns in later time fields.
• Time fields accept absolute TimeSpec strings directly. Cycle offsets use real FSDB clock edges: cycle(clk) means posedge, and posedge(clk) / negedge(clk) choose the edge explicitly.
• For range actions, prefer around/before/after when investigating context around a cursor, for example {"around":"@deadlock","before":"100cycle(top.clk)","after":"20cycle(top.clk)"}.
• Treat value known:false, status:"unknown", and pass:null as inconclusive waveform facts, not failures.
• Use scope.list after SIGNAL_NOT_FOUND.
• Use limits.max_rows/max_events/max_samples for broad scans.
• Load APB/AXI/Event configs before protocol or event actions.
• Runtime state and persisted configs live under ~/.xwave/: registry.json plus sessions/<hashed-session-dir>/session.json, endpoint.json, socket, debug.log, lists.json, apb.json, axi.json, events.json, and cursors.json.
• Transport defaults to UDS. For LSF or multi-host clients, open with args.transport:"tcp" and a reachable bind_host; keep port:0 unless the user explicitly needs a fixed port. The daemon writes the actual auto-assigned TCP port to endpoint.json, so later AI requests still only need target.session_id.

Session Actions

session.open

Open a named session for an FSDB. The session name is required, is the real session id, and is reused by every later target.session_id field. Names may be up to 256 characters and may contain letters, digits, _, ., and -; duplicate names fail. Transport defaults to uds. Use args.transport:"tcp" for TCP; TCP ports are automatically assigned when port is omitted or 0, and the actual endpoint is stored in ~/.xwave/sessions/<hashed-session-dir>/endpoint.json.

{"api_version":"xwave.ai.v1","action":"session.open","target":{"fsdb":"/path/to/waves.fsdb"},"args":{"name":"case_a"}}

{"api_version":"xwave.ai.v1","action":"session.open","target":{"fsdb":"/path/to/waves.fsdb"},"args":{"name":"case_tcp","transport":"tcp","bind_host":"127.0.0.1","port":0}}

session.list

List known sessions. Use before reusing an existing session.

{"api_version":"xwave.ai.v1","action":"session.list"}

session.doctor

Check daemon, transport endpoint, socket/PID, FSDB fingerprint, and health for a session.

{"api_version":"xwave.ai.v1","action":"session.doctor","target":{"session_id":"case_a"}}

session.gc

Clean stale or idle sessions.

{"api_version":"xwave.ai.v1","action":"session.gc"}

session.kill

Stop one session or all sessions.

{"api_version":"xwave.ai.v1","action":"session.kill","args":{"id":"all"}}

Cursor Actions

Cursor actions store named session-local times. Use them when a debug flow has a key event time and later queries need context before or after that point. All later time fields can use @name, @name-20ns, @name+5ns, @name-10cycle(top.clk), @-10ns, or @+5ns.

cursor.set

Create or replace a cursor. The response includes data.resolved_time, so use that as the canonical time for evidence.

{"api_version":"xwave.ai.v1","action":"cursor.set","target":{"session_id":"case_a"},"args":{"name":"deadlock","time":"120340ns","note":"rready stall starts"}}

cursor.get

Fetch one cursor.

{"api_version":"xwave.ai.v1","action":"cursor.get","target":{"session_id":"case_a"},"args":{"name":"deadlock"}}

cursor.list

List cursors and the active cursor.

{"api_version":"xwave.ai.v1","action":"cursor.list","target":{"session_id":"case_a"}}

cursor.use

Set the active cursor, enabling short forms such as @-20ns.

{"api_version":"xwave.ai.v1","action":"cursor.use","target":{"session_id":"case_a"},"args":{"name":"deadlock"}}

cursor.delete

Delete a cursor.

{"api_version":"xwave.ai.v1","action":"cursor.delete","target":{"session_id":"case_a"},"args":{"name":"deadlock"}}

Scope And Value Actions

scope.list

List available FSDB signals under a scope. Use this to recover from missing or ambiguous paths.

{"api_version":"xwave.ai.v1","action":"scope.list","target":{"session_id":"case_a"},"args":{"path":"top.u_dut","recursive":true},"limits":{"max_rows":200}}

value.at

Read one signal at one time. Use for point evidence.

{"api_version":"xwave.ai.v1","action":"value.at","target":{"session_id":"case_a"},"args":{"signal":"top.u_dut.ready","at":"@deadlock-20ns","format":"hex"}}

value.batch_at

Read many signals at the same time. Prefer this over many value.at calls.

{"api_version":"xwave.ai.v1","action":"value.batch_at","target":{"session_id":"case_a"},"args":{"at":"@deadlock","signals":["top.u_dut.valid","top.u_dut.ready","top.u_dut.fifo_full"],"format":"hex"}}

Signal List Actions

list.create

Create a named signal list.

{"api_version":"xwave.ai.v1","action":"list.create","target":{"session_id":"case_a"},"args":{"name":"if0"}}

list.add

Add a signal after probing that it exists.

{"api_version":"xwave.ai.v1","action":"list.add","target":{"session_id":"case_a"},"args":{"name":"if0","signal":"top.u_dut.valid"}}

list.delete

Remove by signal path or list index.

{"api_version":"xwave.ai.v1","action":"list.delete","target":{"session_id":"case_a"},"args":{"name":"if0","index":"2"}}

list.show

Show list members.

{"api_version":"xwave.ai.v1","action":"list.show","target":{"session_id":"case_a"},"args":{"name":"if0"}}

list.value_at

Read all list signals at one time.

{"api_version":"xwave.ai.v1","action":"list.value_at","target":{"session_id":"case_a"},"args":{"name":"if0","time":"42us","format":"binary"}}

list.validate

Check whether every signal in a list exists in the current FSDB.

{"api_version":"xwave.ai.v1","action":"list.validate","target":{"session_id":"case_a"},"args":{"name":"if0"}}

list.diff

Find the earliest time where list values are not all equal.

{"api_version":"xwave.ai.v1","action":"list.diff","target":{"session_id":"case_a"},"args":{"name":"if0","begin":"0ns","end":"100us"}}

APB Actions

apb.config.load

Load and persist an APB config. config_path points to JSON, or config may inline the object.

{"api_version":"xwave.ai.v1","action":"apb.config.load","target":{"session_id":"case_a"},"args":{"name":"apb0","config_path":"apb.json"}}

apb.config.list

Return the saved APB config.

{"api_version":"xwave.ai.v1","action":"apb.config.list","target":{"session_id":"case_a"},"args":{"name":"apb0"}}

apb.query

Query APB reads or writes. Use direction:"wr" or direction:"rd", with optional address, num, or last.

{"api_version":"xwave.ai.v1","action":"apb.query","target":{"session_id":"case_a"},"args":{"name":"apb0","direction":"wr","address":"0x100","num":1}}

apb.cursor

Iterate APB transactions with op:"begin", next, pre, or last.

{"api_version":"xwave.ai.v1","action":"apb.cursor","target":{"session_id":"case_a"},"args":{"name":"apb0","op":"begin","direction":"all"}}

apb.transfer_window

Return APB transactions whose transfer time is inside a time range.

{"api_version":"xwave.ai.v1","action":"apb.transfer_window","target":{"session_id":"case_a"},"args":{"name":"apb0","time_range":{"begin":"40us","end":"45us"},"direction":"all","limit":50}}

AXI Actions

axi.config.load

Load and persist an AXI config. Use a full five-channel config with clk, rst_n, and optional edge.

{"api_version":"xwave.ai.v1","action":"axi.config.load","target":{"session_id":"case_a"},"args":{"name":"axi0","config_path":"axi.json"}}

axi.config.list

Return the saved AXI config.

{"api_version":"xwave.ai.v1","action":"axi.config.list","target":{"session_id":"case_a"},"args":{"name":"axi0"}}

axi.query

Query AXI reads or writes. Use optional address, id, num, or last.

{"api_version":"xwave.ai.v1","action":"axi.query","target":{"session_id":"case_a"},"args":{"name":"axi0","direction":"rd","id":"0x3","num":1}}

axi.cursor

Iterate AXI transactions with op:"begin", next, pre, or last.

{"api_version":"xwave.ai.v1","action":"axi.cursor","target":{"session_id":"case_a"},"args":{"name":"axi0","op":"next","direction":"rd"}}

axi.analysis

Return AXI latency or outstanding statistics. Use analysis:"latency" or analysis:"osd" and optional direction or id.

{"api_version":"xwave.ai.v1","action":"axi.analysis","target":{"session_id":"case_a"},"args":{"name":"axi0","analysis":"latency","direction":"all"}}

axi.channel_stall

Inspect one AXI channel valid/ready stall behavior. Channels: aw, w, b, ar, r.

{"api_version":"xwave.ai.v1","action":"axi.channel_stall","target":{"session_id":"case_a"},"args":{"name":"axi0","channel":"r","time_range":{"begin":"40us","end":"45us"},"rules":{"max_wait_cycles":16}}}

axi.outstanding_timeline

Return outstanding samples over a window. Use for buildup/root-cause evidence.

{"api_version":"xwave.ai.v1","action":"axi.outstanding_timeline","target":{"session_id":"case_a"},"args":{"name":"axi0","time_range":{"begin":"40us","end":"45us"},"direction":"all","limit":100}}

axi.request_response_pair

Return AXI transactions whose request or response time is inside a window.

{"api_version":"xwave.ai.v1","action":"axi.request_response_pair","target":{"session_id":"case_a"},"args":{"name":"axi0","time_range":{"begin":"40us","end":"45us"},"direction":"rd","limit":20}}

axi.latency_outlier

Return transactions with largest request-response latency.

{"api_version":"xwave.ai.v1","action":"axi.latency_outlier","target":{"session_id":"case_a"},"args":{"name":"axi0","time_range":{"begin":"0ns","end":"100us"},"direction":"all","top_n":5,"limit":500}}

Event Actions

event.config.load

Load and persist a generic event config bound to the current FSDB.

{"api_version":"xwave.ai.v1","action":"event.config.load","target":{"session_id":"case_a"},"args":{"name":"if0","config_path":"if0.event.json"}}

event.config.list

List event configs or return one config.

{"api_version":"xwave.ai.v1","action":"event.config.list","target":{"session_id":"case_a"},"args":{"name":"if0"}}

event.find

Find the first clock-sampled event matching an expression.

{"api_version":"xwave.ai.v1","action":"event.find","target":{"session_id":"case_a"},"args":{"name":"if0","expr":"valid && !ready","time_range":{"begin":"40us","end":"45us"}}}

With protocol context:

{"api_version":"xwave.ai.v1","action":"event.find","target":{"session_id":"case_a"},"args":{"name":"if0","expr":"valid && !ready","time_range":{"begin":"40us","end":"45us"},"context":{"window":"200ns","axi":"axi0","apb":"apb0"}}}

event.export

Export matching events. Always set a limit unless you intentionally need a large scan.

{"api_version":"xwave.ai.v1","action":"event.export","target":{"session_id":"case_a"},"args":{"name":"if0","expr":"valid && !ready","time_range":{"begin":"40us","end":"45us"},"limit":100}}

Use aggregate when you need counts instead of full event rows:

{"api_version":"xwave.ai.v1","action":"event.export","target":{"session_id":"case_a"},"args":{"name":"if0","expr":"valid && ready","time_range":{"begin":"0ns","end":"100us"},"aggregate":{"count":true,"group_by":["qid","val"],"events":false}}}

Important: group_by names are not magic built-ins. Every group key must already be defined by the event config as either a signals alias or a fields entry. If qid is a standalone FSDB signal, define it under signals:

{
  "clk": "xring_tb_top.clk",
  "rst_n": "xring_tb_top.rst_n",
  "signals": {
    "valid": "xring_tb_top.credit_init_valid",
    "ready": "xring_tb_top.credit_init_ready",
    "qid": "xring_tb_top.credit_init_qid"
  }
}

If qid is a bit slice inside a payload, define the payload signal and expose qid under fields:

{
  "clk": "xring_tb_top.clk",
  "rst_n": "xring_tb_top.rst_n",
  "signals": {
    "valid": "xring_tb_top.credit_init_valid",
    "ready": "xring_tb_top.credit_init_ready",
    "payload": "xring_tb_top.credit_init_payload"
  },
  "fields": {
    "qid": {"signal": "payload", "left": 7, "right": 4},
    "val": {"signal": "payload", "left": 2, "right": 0}
  }
}

After that, aggregate.group_by:["qid","val"] groups by those configured values. If a group key is missing, unreadable, or contains x/z, it is grouped as unknown.

Wave Fact Verification Actions

verify.conditions

Check point-time conditions. Use this to verify hypotheses generated from RTL or protocol reasoning.

{"api_version":"xwave.ai.v1","action":"verify.conditions","target":{"session_id":"case_a"},"args":{"time":"42us","conditions":[{"signal":"top.u_dut.fifo_full","op":"==","value":"1"},{"signal":"top.u_dut.state","op":"!=","value":"0"}]}}

expr.eval_at

Evaluate a Boolean expression at one time using aliases.

{"api_version":"xwave.ai.v1","action":"expr.eval_at","target":{"session_id":"case_a"},"args":{"time":"42us","signals":{"valid":"top.u_dut.valid","ready":"top.u_dut.ready"},"expr":"valid && !ready"}}

window.verify

Verify expressions sampled on clock edges over a window. mode may be always, never, or eventually.

{"api_version":"xwave.ai.v1","action":"window.verify","target":{"session_id":"case_a"},"args":{"clock":"top.clk","sampling":"posedge","time_range":{"begin":"42us","end":"44us"},"conditions":[{"expr":"valid && !ready","signals":{"valid":"top.u_dut.valid","ready":"top.u_dut.ready"},"mode":"always"}]}}

signal.changes

Return value changes for a signal in a range.

{"api_version":"xwave.ai.v1","action":"signal.changes","target":{"session_id":"case_a"},"args":{"signal":"top.u_dut.fifo_full","time_range":{"begin":"40us","end":"45us"},"limit":20,"format":"binary"}}

signal.stability

Check whether a signal remains stable in a range.

{"api_version":"xwave.ai.v1","action":"signal.stability","target":{"session_id":"case_a"},"args":{"signal":"top.u_dut.active_count","time_range":{"begin":"42us","end":"44us"}}}

signal.trend

Sample a numeric signal on clock edges and summarize monotonicity, min, max, and stable state.

{"api_version":"xwave.ai.v1","action":"signal.trend","target":{"session_id":"case_a"},"args":{"signal":"top.u_dut.active_count","clock":"top.clk","sampling":"posedge","time_range":{"begin":"40us","end":"45us"},"max_samples":10000}}

signal.statistics

Count sampled high/low/unknown cycles and numeric min/max/final values over a clocked range. Prefer this over manual event.export counting for signal-level statistics.

{"api_version":"xwave.ai.v1","action":"signal.statistics","target":{"session_id":"case_a"},"args":{"signal":"top.u_dut.ready","clock":"top.clk","sampling":"posedge","time_range":{"begin":"@stall-100cycle(top.clk)","end":"@stall+20cycle(top.clk)"},"max_samples":1000000}}

sampled_pulse.inspect

Compare raw valid/payload transitions against DUT clock sampling. Use this when raw waveform activity exists but the DUT may not have sampled a valid pulse.

The returned raw_begin/raw_end or raw_time fields are real waveform transition times. previous_sample_edge, next_sample_edge, and nearest_sample_edge are DUT clock sampling edges that explain whether the pulse was visible to the DUT.

{"api_version":"xwave.ai.v1","action":"sampled_pulse.inspect","target":{"session_id":"case_a"},"args":{"clock":"xring_tb_top.clk","valid":"xring_tb_top.credit_init_vld","payload":"xring_tb_top.credit_init_pd","time_range":{"begin":"0ns","end":"200us"},"sampling":"posedge","format":"hex"},"limits":{"max_samples":1000000,"max_findings":20}}

Typical use: inspect summary.risk_count; if nonzero, set a cursor at data.first_risk.raw_begin or data.first_risk.raw_time, then run value.batch_at or signal.statistics around that cursor.

inspect_signal

Summarize signal transitions, period-like intervals, and glitches.

{"api_version":"xwave.ai.v1","action":"inspect_signal","target":{"session_id":"case_a"},"args":{"signal":"top.clk","time_range":{"begin":"0ns","end":"1us"},"glitch_threshold":"1ns","limit":1000}}

detect_anomaly

Find waveform anomalies such as glitches, stuck values, and x/z.

{"api_version":"xwave.ai.v1","action":"detect_anomaly","target":{"session_id":"case_a"},"args":{"signals":["top.u_dut.ready","top.u_dut.valid","top.u_dut.data"],"time_range":{"begin":"0ns","end":"100us"},"checks":[{"type":"glitch","min_pulse_width":"1ns"},{"type":"stuck","min_duration":"1us"},{"type":"unknown_xz"}],"max_findings":50}}

handshake.inspect

Analyze a generic valid/ready interface sampled on a clock.

{"api_version":"xwave.ai.v1","action":"handshake.inspect","target":{"session_id":"case_a"},"args":{"clock":"top.clk","valid":"top.u_dut.valid","ready":"top.u_dut.ready","data":["top.u_dut.data"],"time_range":{"begin":"40us","end":"45us"},"rules":{"max_wait_cycles":100,"check_data_stable_when_stalled":true}}}

Recommended AI Workflows

Point fact verification

1. session.open
2. value.batch_at
3. If missing signal: scope.list
4. Store data.values[] as evidence.

Valid/ready stall debug

1. handshake.inspect for generic interfaces, or axi.channel_stall for AXI channels.
2. Use value.batch_at at stall begin/mid/end for related control signals.
3. Use window.verify to prove the blocking condition persists.
4. Use event.find or event.export when you need exact event samples.

Protocol context around an event

1. axi.config.load and/or apb.config.load
2. event.config.load
3. event.find with context.window plus context.axi and/or context.apb
4. Use returned transactions and delta_ps as evidence.

Performance-safe scanning

Use bounded ranges and limits:

{"limits":{"max_rows":100,"max_events":100,"max_samples":100000}}

Prefer:

• value.batch_at over repeated value.at
• event.find before event.export
• signal.statistics before exporting events just to count high/low cycles
• event.export with aggregate.events:false before exporting full event rows for counts
• axi.channel_stall before full AXI transaction inspection
• signal.stability before full signal.changes

Error Handling

Common error.code values:

Code	AI response
SIGNAL_NOT_FOUND	Run scope.list near the parent scope and retry with a candidate path.
SESSION_NOT_FOUND / SESSION_UNHEALTHY	Run session.list, session.doctor, or reopen the FSDB.
INVALID_REQUEST / MISSING_FIELD	Fix the JSON request shape before retrying.
EXPR_PARSE_FAILED	Simplify or validate aliases in the expression.
WAVE_QUERY_FAILED	Check FSDB, config binding, and time range.

If ok:false, do not use data as evidence. If ok:true but a value has known:false, preserve it as unknown evidence rather than converting it to pass/fail.