# Runs and conversations

An agent answering one question can make dozens of model calls: planning, tool calls, retries, a summary. Tag them with the same `run` and Veqen adds them up, so you can see what each run cost, what a typical one costs, and which ones ran away.

## Tag a run

Any id that's the same for every call in the run works: a conversation id, a job id, a trace id.

```python [Python]
with veqen.tags(run=conversation.id, customer=account.id):
    answer = agent.run(question)
```

```ts [TypeScript]
await withTags({ run: conversation.id, customer: account.id }, () => agent.run(question));
```

The [OpenAI Agents SDK](/integrations/openai-agents) processor tags each agent run with its trace id for you. Over [OpenTelemetry](/docs/opentelemetry), `veqen.run`, `gen_ai.conversation.id` or `ai.telemetry.metadata.run` set it. Ids are up to 128 characters; send them on every call of the run, including retries.

## What you see

**Agent runs** shows, for the dates you pick:

- how many runs ended, and what they cost in all;
- **a typical run** (the median: half cost less, half more), and the **90th** and **99th percentile** runs;
- how run cost spreads, in bands from cents to dollars, so a long tail stands out;
- the most expensive runs, each opening to its calls in order, with the model, tokens and cost of each step.

Filters from Breakdown (a customer, a feature) carry over, so you can compare one customer's runs with everyone's. A run's page shows its last 31 days of calls if the same id is reused for longer.

## Use it

- **Price an agent.** The median and p90 run cost are what you need to set a per-task price or a plan limit.
- **Find runaway loops.** A run in the top band that made hundreds of calls is usually a tool loop or a retry storm.
- **Watch a change.** Compare the run spread before and after a prompt or model change.

With a full-access key, `GET /v1/runs` returns the count, total, average, typical (`median_about`) and 90th percentile (`p90_about`) run and the most expensive runs, and `GET /v1/runs/{run}` one run's calls in order; over MCP, `get_runs` and `get_run`.

Runs are counted as calls arrive, so they're current to the last ingest. The run id isn't a dimension in Breakdown; filter by customer or feature there and open Agent runs for the per-run view.