# Common attributes

> Attributes shared by every span or metric: the chain, the operation and error.type. Type, spans, default and meaning of each.

Source: https://hashspan.dev/docs/reference/attributes/common

Generated from the semantic conventions These rows are generated from the semantic conventions at @hashspan/core@1.1.0, the version on npm. They are a draft: names can still change.

Attributes shared by every span or metric: the chain, the operation and `error.type`. *Default* is what is recorded without configuration; addresses follow the address mode described under [privacy](https://hashspan.dev/docs/reference/semantic-conventions#privacy).

## `blockchain.system.name`

| Type | Spans | Default |
|---|---|---|
| string | send, confirm, payment | on |

`evm`

## `blockchain.chain.id`

| Type | Spans | Default |
|---|---|---|
| int | all | on |

EIP-155 chain id, e.g. `8453`

## `blockchain.operation.name`

| Type | Spans | Default |
|---|---|---|
| string | send, confirm, payment | on |

`send` | `confirm` | `payment`

## `blockchain.operation.subject`

| Type | Spans | Default |
|---|---|---|
| string | none (metrics only) | on |

on [metrics](https://hashspan.dev/docs/reference/semantic-conventions#metrics) of user operations: `user_operation`; of call batches: `call_batch`; absent on those of transactions

## `blockchain.fee.payer`

| Type | Spans | Default |
|---|---|---|
| string | none (metrics only) | on |

on `blockchain.client.fee` samples whose fee the sender of the traced transaction or operation did not pay: `facilitator` for a payment's settlement transaction, `paymaster` for a user operation a paymaster paid for, `sponsor` for a transaction whose receipt names another account as its fee payer (a Tempo `feePayer`); a payment's settlement keeps `facilitator`, also when its fee was sponsored; absent when the sender paid ([ADR 0020](https://github.com/selimaytac/hashspan/blob/@hashspan/core@1.1.0/docs/adr/0020-metrics.md))

## `blockchain.fee.denomination`

| Type | Spans | Default |
|---|---|---|
| string | none (metrics only) | on |

on `blockchain.client.fee` samples whose fee was paid in a token rather than the chain's native currency: `token`, a constant, never an address or a value read from the chain; set whenever `blockchain.tx.fee_asset` is known, in every address mode; absent for the native currency, Arc's USDC included ([ADR 0028](https://github.com/selimaytac/hashspan/blob/@hashspan/core@1.1.0/docs/adr/0028-fee-asset.md))

## `error.type`

| Type | Spans | Default |
|---|---|---|
| string | all | on |

see *Span status*; reused from OpenTelemetry general conventions