Agent skill

arize-trace

INVOKE THIS SKILL when downloading or exporting Arize traces and spans. Covers exporting traces by ID, sessions by ID, and debugging LLM application issues using the ax CLI.

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Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/arize-trace

SKILL.md

Arize Trace Skill

Concepts

  • Trace = a tree of spans sharing a context.trace_id, rooted at a span with parent_id = null
  • Span = a single operation (LLM call, tool call, retriever, chain, agent)
  • Session = a group of traces sharing attributes.session.id (e.g., a multi-turn conversation)

Use ax spans export to download individual spans, or ax traces export to download complete traces (all spans belonging to matching traces).

Resolving project for export: The PROJECT positional argument accepts either a project name or a base64 project ID. When using a name, --space-id is required. If you hit limit errors or 401 Unauthorized when using a project name, resolve it to a base64 ID: run ax projects list --space-id SPACE_ID -l 100 -o json, find the project by name, and use its id as PROJECT.

Exploratory export rule: When exporting spans or traces without a specific --trace-id, --span-id, or --session-id (i.e., browsing/exploring a project), always start with -l 50 to pull a small sample first. Summarize what you find, then pull more data only if the user asks or the task requires it. This avoids slow queries and overwhelming output on large projects.

Default output directory: Always use --output-dir .arize-tmp-traces on every ax spans export call. The CLI automatically creates the directory and adds it to .gitignore.

Prerequisites

Three things are needed: ax CLI, an API key (env var or profile), and a space ID. A project name or ID is also needed but usually comes from the user's message.

Install ax

If ax is not installed, not on PATH, or below version 0.3.0, see ax-setup.md.

Verify environment

Run a quick check for credentials:

macOS/Linux (bash):

bash
ax --version && echo "--- env ---" && if [ -n "$ARIZE_API_KEY" ]; then echo "ARIZE_API_KEY: (set)"; else echo "ARIZE_API_KEY: (not set)"; fi && echo "ARIZE_SPACE_ID: ${ARIZE_SPACE_ID:-(not set)}" && echo "--- profiles ---" && ax profiles show 2>&1

Windows (PowerShell):

powershell
ax --version; Write-Host "--- env ---"; Write-Host "ARIZE_API_KEY: $(if ($env:ARIZE_API_KEY) { '(set)' } else { '(not set)' })"; Write-Host "ARIZE_SPACE_ID: $env:ARIZE_SPACE_ID"; Write-Host "--- profiles ---"; ax profiles show 2>&1

Read the output and proceed immediately if either the env var or the profile has an API key. Only ask the user if both are missing. Resolve failures:

  • No API key in env and no profile → AskQuestion: "Arize API key (https://app.arize.com/admin > API Keys)"
  • Space ID unknown → run ax spaces list -o json to list all accessible spaces and pick the right one, or AskQuestion if the user prefers to provide it directly
  • Project unclear → run ax projects list -l 100 -o json (add --space-id if known), present the names, and ask the user to pick one

IMPORTANT: --space-id is required when using a human-readable project name as the PROJECT positional argument. It is not needed when using a base64-encoded project ID. If you hit 401 Unauthorized or limit errors when using a project name, resolve it to a base64 ID first (see "Resolving project for export" in Concepts).

Export Spans: ax spans export

The primary command for downloading trace data to a file.

By trace ID

bash
ax spans export PROJECT_ID --trace-id TRACE_ID --output-dir .arize-tmp-traces

By span ID

bash
ax spans export PROJECT_ID --span-id SPAN_ID --output-dir .arize-tmp-traces

By session ID

bash
ax spans export PROJECT_ID --session-id SESSION_ID --output-dir .arize-tmp-traces

Flags

Flag Default Description
PROJECT (positional) $ARIZE_DEFAULT_PROJECT Project name or base64 ID
--trace-id Filter by context.trace_id (mutex with other ID flags)
--span-id Filter by context.span_id (mutex with other ID flags)
--session-id Filter by attributes.session.id (mutex with other ID flags)
--filter SQL-like filter; combinable with any ID flag
--limit, -l 500 Max spans (REST); ignored with --all
--space-id Required when PROJECT is a name, or with --all
--days 30 Lookback window; ignored if --start-time/--end-time set
--start-time / --end-time ISO 8601 time range override
--output-dir .arize-tmp-traces Output directory
--stdout false Print JSON to stdout instead of file
--all false Unlimited bulk export via Arrow Flight (see below)

Output is a JSON array of span objects. File naming: {type}_{id}_{timestamp}/spans.json.

Bulk export with --all

By default, ax spans export is capped at 500 spans by -l. Pass --all for unlimited bulk export.

bash
ax spans export PROJECT_ID --space-id SPACE_ID --filter "status_code = 'ERROR'" --all --output-dir .arize-tmp-traces

When to use --all:

  • Exporting more than 500 spans
  • Downloading full traces with many child spans
  • Large time-range exports

Agent auto-escalation rule: If an export returns exactly the number of spans requested by -l (or 500 if no limit was set), the result is likely truncated. Increase -l or re-run with --all to get the full dataset — but only when the user asks or the task requires more data.

Decision tree:

Do you have a --trace-id, --span-id, or --session-id?
├─ YES: count is bounded → omit --all. If result is exactly 500, re-run with --all.
└─ NO (exploratory export):
    ├─ Just browsing a sample? → use -l 50
    └─ Need all matching spans?
        ├─ Expected < 500 → -l is fine
        └─ Expected ≥ 500 or unknown → use --all
            └─ Times out? → batch by --days (e.g., --days 7) and loop

Check span count first: Before a large exploratory export, check how many spans match your filter:

bash
# Count matching spans without downloading them
ax spans export PROJECT_ID --filter "status_code = 'ERROR'" -l 1 --stdout | jq 'length'
# If returns 1 (hit limit), run with --all
# If returns 0, no data matches -- check filter or expand --days

Requirements for --all:

  • --space-id is required (Flight uses space_id + project_name, not project_id)
  • --limit is ignored when --all is set

Networking notes for --all: Arrow Flight connects to flight.arize.com:443 via gRPC+TLS -- this is a different host from the REST API (api.arize.com). On internal or private networks, the Flight endpoint may use a different host/port. Configure via:

  • ax profile: flight_host, flight_port, flight_scheme
  • Environment variables: ARIZE_FLIGHT_HOST, ARIZE_FLIGHT_PORT, ARIZE_FLIGHT_SCHEME

The --all flag is also available on ax traces export, ax datasets export, and ax experiments export with the same behavior (REST by default, Flight with --all).

Export Traces: ax traces export

Export full traces -- all spans belonging to traces that match a filter. Uses a two-phase approach:

  1. Phase 1: Find spans matching --filter (up to --limit via REST, or all via Flight with --all)
  2. Phase 2: Extract unique trace IDs, then fetch every span for those traces
bash
# Explore recent traces (start small with -l 50, pull more if needed)
ax traces export PROJECT_ID -l 50 --output-dir .arize-tmp-traces

# Export traces with error spans (REST, up to 500 spans in phase 1)
ax traces export PROJECT_ID --filter "status_code = 'ERROR'" --stdout

# Export all traces matching a filter via Flight (no limit)
ax traces export PROJECT_ID --space-id SPACE_ID --filter "status_code = 'ERROR'" --all --output-dir .arize-tmp-traces

Flags

Flag Type Default Description
PROJECT string required Project name or base64 ID (positional arg)
--filter string none Filter expression for phase-1 span lookup
--space-id string none Space ID; required when PROJECT is a name or when using --all (Arrow Flight)
--limit, -l int 50 Max number of traces to export
--days int 30 Lookback window in days
--start-time string none Override start (ISO 8601)
--end-time string none Override end (ISO 8601)
--output-dir string . Output directory
--stdout bool false Print JSON to stdout instead of file
--all bool false Use Arrow Flight for both phases (see spans --all docs above)
-p, --profile string default Configuration profile

How it differs from ax spans export

  • ax spans export exports individual spans matching a filter
  • ax traces export exports complete traces -- it finds spans matching the filter, then pulls ALL spans for those traces (including siblings and children that may not match the filter)

Filter Syntax Reference

SQL-like expressions passed to --filter.

Common filterable columns

Column Type Description Example Values
name string Span name 'ChatCompletion', 'retrieve_docs'
status_code string Status 'OK', 'ERROR', 'UNSET'
latency_ms number Duration in ms 100, 5000
parent_id string Parent span ID null for root spans
context.trace_id string Trace ID
context.span_id string Span ID
attributes.session.id string Session ID
attributes.openinference.span.kind string Span kind 'LLM', 'CHAIN', 'TOOL', 'AGENT', 'RETRIEVER', 'RERANKER', 'EMBEDDING', 'GUARDRAIL', 'EVALUATOR'
attributes.llm.model_name string LLM model 'gpt-4o', 'claude-3'
attributes.input.value string Span input
attributes.output.value string Span output
attributes.error.type string Error type 'ValueError', 'TimeoutError'
attributes.error.message string Error message
event.attributes string Error tracebacks Use CONTAINS (not exact match)

Operators

=, !=, <, <=, >, >=, AND, OR, IN, CONTAINS, LIKE, IS NULL, IS NOT NULL

Examples

status_code = 'ERROR'
latency_ms > 5000
name = 'ChatCompletion' AND status_code = 'ERROR'
attributes.llm.model_name = 'gpt-4o'
attributes.openinference.span.kind IN ('LLM', 'AGENT')
attributes.error.type LIKE '%Transport%'
event.attributes CONTAINS 'TimeoutError'

Tips

  • Prefer IN over multiple OR conditions: name IN ('a', 'b', 'c') not name = 'a' OR name = 'b' OR name = 'c'
  • Start broad with LIKE, then switch to = or IN once you know exact values
  • Use CONTAINS for event.attributes (error tracebacks) -- exact match is unreliable on complex text
  • Always wrap string values in single quotes

Workflows

Debug a failing trace

  1. ax traces export PROJECT_ID --filter "status_code = 'ERROR'" -l 50 --output-dir .arize-tmp-traces
  2. Read the output file, look for spans with status_code: ERROR
  3. Check attributes.error.type and attributes.error.message on error spans

Download a conversation session

  1. ax spans export PROJECT_ID --session-id SESSION_ID --output-dir .arize-tmp-traces
  2. Spans are ordered by start_time, grouped by context.trace_id
  3. If you only have a trace_id, export that trace first, then look for attributes.session.id in the output to get the session ID

Export for offline analysis

bash
ax spans export PROJECT_ID --trace-id TRACE_ID --stdout | jq '.[]'

Span Column Reference (OpenInference Semantic Conventions)

Core Identity and Timing

Column Description
name Span operation name (e.g., ChatCompletion, retrieve_docs)
context.trace_id Trace ID -- all spans in a trace share this
context.span_id Unique span ID
parent_id Parent span ID. null for root spans (= traces)
start_time When the span started (ISO 8601)
end_time When the span ended
latency_ms Duration in milliseconds
status_code OK, ERROR, UNSET
status_message Optional message (usually set on errors)
attributes.openinference.span.kind LLM, CHAIN, TOOL, AGENT, RETRIEVER, RERANKER, EMBEDDING, GUARDRAIL, EVALUATOR

Where to Find Prompts and LLM I/O

Generic input/output (all span kinds):

Column What it contains
attributes.input.value The input to the operation. For LLM spans, often the full prompt or serialized messages JSON. For chain/agent spans, the user's question.
attributes.input.mime_type Format hint: text/plain or application/json
attributes.output.value The output. For LLM spans, the model's response. For chain/agent spans, the final answer.
attributes.output.mime_type Format hint for output

LLM-specific message arrays (structured chat format):

Column What it contains
attributes.llm.input_messages Structured input messages array (system, user, assistant, tool). Where chat prompts live in role-based format.
attributes.llm.input_messages.roles Array of roles: system, user, assistant, tool
attributes.llm.input_messages.contents Array of message content strings
attributes.llm.output_messages Structured output messages from the model
attributes.llm.output_messages.contents Model response content
attributes.llm.output_messages.tool_calls.function.names Tool calls the model wants to make
attributes.llm.output_messages.tool_calls.function.arguments Arguments for those tool calls

Prompt templates:

Column What it contains
attributes.llm.prompt_template.template The prompt template with variable placeholders (e.g., "Answer {question} using {context}")
attributes.llm.prompt_template.variables Template variable values (JSON object)

Finding prompts by span kind:

  • LLM span: Check attributes.llm.input_messages for structured chat messages, OR attributes.input.value for serialized prompt. Check attributes.llm.prompt_template.template for the template.
  • Chain/Agent span: Check attributes.input.value for the user's question. Actual LLM prompts are on child LLM spans.
  • Tool span: Check attributes.input.value for tool input, attributes.output.value for tool result.

LLM Model and Cost

Column Description
attributes.llm.model_name Model identifier (e.g., gpt-4o, claude-3-opus-20240229)
attributes.llm.invocation_parameters Model parameters JSON (temperature, max_tokens, top_p, etc.)
attributes.llm.token_count.prompt Input token count
attributes.llm.token_count.completion Output token count
attributes.llm.token_count.total Total tokens
attributes.llm.cost.prompt Input cost in USD
attributes.llm.cost.completion Output cost in USD
attributes.llm.cost.total Total cost in USD

Tool Spans

Column Description
attributes.tool.name Tool/function name
attributes.tool.description Tool description
attributes.tool.parameters Tool parameter schema (JSON)

Retriever Spans

Column Description
attributes.retrieval.documents Retrieved documents array
attributes.retrieval.documents.ids Document IDs
attributes.retrieval.documents.scores Relevance scores
attributes.retrieval.documents.contents Document text content
attributes.retrieval.documents.metadatas Document metadata

Reranker Spans

Column Description
attributes.reranker.query The query being reranked
attributes.reranker.model_name Reranker model
attributes.reranker.top_k Number of results
attributes.reranker.input_documents.* Input documents (ids, scores, contents, metadatas)
attributes.reranker.output_documents.* Reranked output documents

Session, User, and Custom Metadata

Column Description
attributes.session.id Session/conversation ID -- groups traces into multi-turn sessions
attributes.user.id End-user identifier
attributes.metadata.* Custom key-value metadata. Any key under this prefix is user-defined (e.g., attributes.metadata.user_email). Filterable.

Errors and Exceptions

Column Description
attributes.exception.type Exception class name (e.g., ValueError, TimeoutError)
attributes.exception.message Exception message text
event.attributes Error tracebacks and detailed event data. Use CONTAINS for filtering.

Evaluations and Annotations

Column Description
annotation.<name>.label Human or auto-eval label (e.g., correct, incorrect)
annotation.<name>.score Numeric score (e.g., 0.95)
annotation.<name>.text Freeform annotation text

Embeddings

Column Description
attributes.embedding.model_name Embedding model name
attributes.embedding.texts Text chunks that were embedded

Troubleshooting

Problem Solution
ax: command not found See ax-setup.md
SSL: CERTIFICATE_VERIFY_FAILED macOS: export SSL_CERT_FILE=/etc/ssl/cert.pem. Linux: export SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt. Windows: $env:SSL_CERT_FILE = (python -c "import certifi; print(certifi.where())")
No such command on a subcommand that should exist The installed ax is outdated. Reinstall: uv tool install --force --reinstall arize-ax-cli (requires shell access to install packages)
No profile found Follow "Resolve credentials" in Prerequisites to auto-discover or prompt for the API key
401 Unauthorized with valid API key You are likely using a project name without --space-id. Add --space-id SPACE_ID, or resolve to a base64 project ID first: ax projects list --space-id SPACE_ID -l 100 -o json and use the project's id.
No spans found Expand --days (default 30), verify project ID
Filter error or invalid filter expression Check column name spelling (e.g., attributes.openinference.span.kind not span_kind), wrap string values in single quotes, use CONTAINS for free-text fields
unknown attribute in filter The attribute path is wrong or not indexed. Try browsing a small sample first to see actual column names: ax spans export PROJECT_ID -l 5 --stdout | jq '.[0] | keys'
Timeout on large export Use --days 7 to narrow the time range

Related Skills

  • arize-dataset: After collecting trace data, create labeled datasets for evaluation → use arize-dataset
  • arize-experiment: Run experiments comparing prompt versions against a dataset → use arize-experiment
  • arize-prompt-optimization: Use trace data to improve prompts → use arize-prompt-optimization
  • arize-link: Turn trace IDs from exported data into clickable Arize UI URLs → use arize-link

Save Credentials

At session end, if the user manually provided an API key, space ID, or project ID (not loaded from an existing profile), offer to save them to ~/.arize/config.toml. Use AskQuestion with "Yes, save them" / "No thanks". Skip if all values were already in the profile.

Read the existing file (or create it), add/update only the new fields, and write it back:

toml
[auth]
api_key = "THE_API_KEY"

[defaults]
space_id = "THE_SPACE_ID"
project = "THE_PROJECT_NAME"

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