5to1r
Agent Observability Infrastructure

Every step youragent |

5to1r instruments your AI agents in two lines of code. See every tool call, LLM decision, and dollar spent — in real time. Debug in minutes, not hours.

Install the SDK. Run your agent. Watch spans appear live.

Open-source SDK
Works with any LLM
First span in 5 minutes
Free up to 50,000 spans
live trace
run_8f21a9
llm_call
claude-sonnet-4-5
420ms
$1.86
tool_call
web_search
180ms
$0.42
decision
route_to_summary
32ms
$0.00
llm_call
gpt-4o-mini
310ms
$1.24
run_end
completed
1.24s
$3.52
Total cost: $3.52Duration: 1.24sSpans: 5
PROBLEM

Agents fail silently.
You have no idea why.

When something breaks, you're left digging through logs, guessing what happened, and trying to reconstruct the run step by step.

live tracerun_8fa21c
initializing
initializing system...
Span Distribution
[██████░░███████████░░]
cost: $0.000duration: 12.44s
status: initializing
01

NO_VISIBILITY

Your agent calls 12 tools and 6 LLMs in a single run. Which step cost $40? Which one failed? Right now, you have no way to know.

02

NO_DEBUGGING

When something goes wrong, you stare at raw logs and try to reconstruct what happened. A failed run can take hours to diagnose.

03

NO_COST CONTROL

Runaway loops. Infinite context windows. Retries. Your LLM bill arrives and you have no idea what ran up the cost.

workspace — tty1
>
>

Catch the next one.

One decorator turns the next run into a trace.

No config files. No framework lock-in. No infrastructure to wire.

main.pyDiff
+async def research_agent(query):
+ return await run(query)
small code change
next run captured
run_idrun_91d7c2
spans23
retries2
cost$1.12
status
visible
previous run: wasted $18.42|next run: visible

Every run becomes inspectable.

5to1r turns one agent run into a trace, cost map, retry trail, and failure record.

TRACE
tool_callllm_callretryerror
COST
$0.74$1.12$4.38
RETRIES
web_search×7
FAILURE
timeout/partial_output
APPLICATIONS

Built for complexity.

RESEARCH

Agents that browse, summarize, and synthesize information

They call multiple tools, retry queries, and generate inconsistent outputs. You don’t know which step failed or why the answer changed.

01> tool_call web_search
02> retry attempt 3
03> llm_call failed (timeout)
04> partial_output_streamed
SUPPORT

Agents handling user conversations in production

Context grows, responses drift, and failures are unpredictable. When something breaks, you can’t replay what the agent saw.

01> tokens_consumed: 12,402
02> drift_detected (confidence: 0.12)
03> response_malformed_json
04> session_terminated_unexpectedly
AUTOMATION

Agents executing multi-step workflows

Dozens of steps, retries, and edge cases. A single failure breaks the chain, and you have no visibility into where it happened.

01> executing_step: 14/32
02> db_lock_retry: true
03> chain_break: step_15_failed
04> rollback_initiated
TOOL CALLING

Agents calling APIs and external tools

They loop, retry, and escalate costs silently. Your API bill increases, but you don’t know what caused it.

01> tool_call search_db
02> loop_detected: cycle_4
03> cost_escalation: +$1.42
04> run_aborted (safety_limit)

Start free. Scale when your agents do.

Use 5to1r free while you build. Upgrade when you need replay, longer history, alerts, team workflows, or enterprise controls.

Annual prices shown as effective monthly rates.

Pro

For agents running in production.

$49/ month
spans/month
5,000,000
history
90 days
run replay
included
cost alerts
included
slack alerts
included
projects
10
team seats
5 included
extra seats
$19 / seat / month
Team

For teams with heavy agent workloads.

$299/ month
spans/month
50,000,000
history
1 year
run replay
included
eval engine
included
alerts
email + slack
projects
unlimited
team seats
10 included
extra seats
$29 / seat / month
Enterprise

For organizations with compliance and residency requirements.

Custom
span volumecustom
retentioncustom
sso / samlincluded
audit logsincluded
data residencyavailable
deploymenton-prem option
dedicated engineerincluded
slaguaranteed
Free
$0/ month

For testing and early agent builds.

No credit card required for Free. Upgrade when your volume grows.

Run your first trace.

Instrument your agent, run it once, and see every step it takes.

Free plan included. No credit card. First trace in minutes.

$pip install 5to1r
$run-agent
trace ready: run_8f21a9