This NIP defines `kind:30175` persona events — public, addressable definitions that describe how to instantiate an AI agent. A persona carries identity (display name, avatar), behavioral configuration (system prompt, model, runtime), and an optional name pool. It is the "blueprint" from which agents are spawned.
## Kind
This NIP claims `kind:30175` for agent persona definitions. It is in the NIP-33 parameterized replaceable range (30000–39999) per [NIP-01](01.md): addressed by `(pubkey, kind, d_tag)`, with only the latest event per address retained.
A dedicated kind (rather than encoding personas as NIP-78 `kind:30078` "Application-specific Data") is taken for the same reasons as [NIP-AE](NIP-AE.md): (1) it isolates this NIP's address space from any other application using the same pubkey — persona slugs cannot collide with another app's `d` tag choices; (2) it lets observers, indexers, and unknown-kind viewers identify persona events from the kind alone, without parsing content as a namespace demultiplexer.
## Roles
- **owner** — a Nostr identity (`pubkey_o`) that publishes and manages persona definitions. Typically the workspace operator.
- **agent** — a Nostr identity instantiated from a persona. Agents do NOT author persona events; they consume them. An agent MAY store a private snapshot of its originating persona in a [NIP-AE](NIP-AE.md) engram at `mem/persona` (encrypted, owner-readable).
## Slugs
The `d` tag of a persona event is the **plaintext persona slug**. A valid slug matches:
```
^[a-z0-9][a-z0-9_-]{0,63}$
```
Total length: 1–64 bytes. Slugs are flat identifiers (no path separators), unlike [NIP-AE](NIP-AE.md) memory slugs which are hierarchical (`mem/…`).
### Plaintext rationale
The d-tag is deliberately NOT blinded (contrast with [NIP-AE](NIP-AE.md) which HMAC-blinds d-tags to protect memory slug confidentiality). Personas are public definitions meant for discovery:
- Direct filter queries: `{kinds: [30175], authors: [pubkey], "#d": ["my-persona"]}`
- Human-readable addressing in UIs
- Cross-workspace sharing without a shared secret
## Event envelope
```jsonc
{
"kind":30175,
"pubkey":"<pubkey_o>",
"created_at":<unix_seconds>,
"tags":[
["d","<persona-slug>"]
],
"content":"<json_body>"
}
```
There MUST be exactly one `d` tag and it MUST contain a valid slug per the grammar above. The relay enforces this constraint on ingest. There is no `p` tag — persona events are owner-to-self definitions, not directed at a counterparty.
Implementations MAY include a [NIP-31](31.md) `["alt", "agent persona definition"]` tag to give unknown-kind viewers a non-leaking summary. Additional tags beyond `d` and `alt` are not defined by this NIP and have no effect on validity.
## Content body
The `content` field is a **plaintext** (unencrypted) JSON object:
| `system_prompt` | string \| null | `null` | The system prompt injected into agent sessions. Optional since the unified agent model: a definition can be pure configuration (e.g. provider/model only). Readers MUST treat an absent or `null` prompt as "no prompt". |
| `name_pool` | string[] | `[]` | Pool of display names for agent instances spawned from this definition. When non-empty, the spawning system picks a name from this pool for each new agent instance, enabling multiple concurrent agents from the same definition to have distinct identities. |
| `respond_to` | string \| null | `null` | **Reserved.** Default respond-to policy for instances spawned from this definition: `"anyone"`, `"owner-only"`, or `"allowlist"`. `null` defers to the client default. |
Unknown fields MUST be ignored by readers (forward compatibility).
### Prohibited: secrets in content
The content body is **public and unencrypted**. It MUST NOT contain secrets (API keys, tokens, credentials, or any sensitive environment variables). In particular, an `env_vars` field MUST NOT appear in the content body.
Secrets required by agents spawned from a persona MUST be conveyed through a separate encrypted channel — specifically, the [NIP-AE](NIP-AE.md) engram at `mem/persona` (which is NIP-44 encrypted to the agent↔owner conversation key) or through out-of-band injection at spawn time.
## Encryption rationale
Persona events carry no encryption. This is deliberate:
- Personas are *configuration*, not *state*. They describe what an agent should be, not what it has learned.
- Encryption would prevent relay-side indexing, search, and third-party client rendering — all desirable for definitions that workspace members should browse.
- Operators who need confidentiality should use relay-level access control ([NIP-42](42.md) authentication + [NIP-29](29.md) group membership) rather than event-level encryption.
## Replacement semantics
Standard NIP-33: for a given `(pubkey, kind:30175, d_tag)`, only the event with the greatest `created_at` is the **head**. Ties are broken by lowest event `id` per [NIP-01](01.md). Relays SHOULD return only the head; clients MUST select the head from any multi-event response.
## Writing
To write or update a persona with slug `s` and body `b`:
1. Validate `s` against the slug grammar. Reject if invalid.
2. Serialize `b` to JSON. Reject if the serialized body exceeds 65,535 bytes.
3. Compute the head of `s` per NIP-33 and let `T` be its `created_at` (or 0 if no head exists). Set `created_at := max(now, T + 1)`. Monotonicity ensures fresh writes always supersede prior heads regardless of clock skew.
4. Tags: `[["d", s]]`.
5. Sign with `seckey_o` and publish to configured relays.
Select the head per NIP-33 rules. Parse `content` as JSON. Validate required fields.
To list all personas for an owner:
```
Filter: {kinds: [30175], authors: [pubkey_o]}
```
Returns all heads. Clients scope by author pubkey — two different owners MAY publish personas with the same slug; these are independent events.
## Deletion
Owners MAY publish [NIP-09](09.md) deletion requests targeting persona events. A deletion request MUST be authored by the same key (`pubkey_o`). Such requests SHOULD include `["k", "30175"]` and use an `a`-tag identifier `30175:<pubkey_o>:<slug>`.
A subsequent write with a later timestamp resurrects the slug under NIP-33 replacement semantics.
## Relationships to other NIPs
### NIP-AE (Agent Engrams)
Agents spawned from a persona MAY store a private snapshot at the reserved engram slug `mem/persona`. This engram:
- Is NIP-44 encrypted (confidential to agent + owner)
- MAY contain secrets (env vars, API keys) that the public persona event must not carry
- Serves as the agent's private, mutable copy of its originating configuration
- References back to the persona event by slug convention, not by event ID
The `mem/persona` slug conforms to [NIP-AE](NIP-AE.md)'s slug grammar and requires no amendment to that spec.
Agents spawned from a persona carry [NIP-OA](NIP-OA.md) owner attestation — an `auth` tag proving that `pubkey_o` authorized the agent's key. The persona event itself does not contain attestation; it is the *definition* from which attestation is issued at spawn time.
## Relay behavior
- The relay MUST accept `kind:30175` events that pass standard NIP-33 validation (valid signature, exactly one `d` tag with a non-empty value).
- The relay stores persona events globally (`channel_id = NULL`); they are not channel-scoped.
- The relay is NOT required to validate that `content` parses as valid `PersonaEventContent` JSON. Relays are dumb stores per Nostr convention; content validation is a client responsibility.
- The relay MUST enforce that the `d` tag is non-empty (standard NIP-33 requirement for parameterized replaceable events).
## Security considerations
- **No encryption.** System prompts, model names, runtime identifiers, and all configuration are visible to anyone with relay read access. Operators MUST NOT store secrets in persona event content.
- **System prompt sensitivity.** System prompts may contain security-relevant behavioral instructions. Publishing them unencrypted enables adversarial prompt extraction. Operators who consider system prompts confidential SHOULD NOT publish them in persona events, or SHOULD use a relay with appropriate access controls.
- **Write authority.** Only the holder of `seckey_o` can publish or replace persona events. NIP-33 replacement is scoped by pubkey — no spoofing risk from other relay members.
- **Slug collision across pubkeys.** Two different owners can publish personas with the same slug. Clients MUST always scope queries by author pubkey, not just slug.
- **Metadata exposure.** The `(pubkey, kind:30175, slug)` triple reveals persona existence. Event timestamps reveal edit history.
- **No owner write authority over agents.** Persona events define *what* an agent should be; they do not grant runtime control over a running agent. The agent consumes the persona at spawn time. Updates to the persona event do not automatically propagate to running agents.
## Reference test vectors
> **TEST KEYS — DO NOT USE IN PRODUCTION.** The keys below are pinned for reproducibility. Production code MUST source randomness from a CSPRNG.
{"display_name":"Test Agent","system_prompt":"You are a test assistant.","avatar_url":"https://example.com/avatar.png","runtime":"goose","model":"claude-opus-4","provider":"anthropic","name_pool":["Alpha","Beta"]}
content = {"display_name":"Test Agent","system_prompt":"You are a test assistant.","avatar_url":"https://example.com/avatar.png","runtime":"goose","model":"claude-opus-4","provider":"anthropic","name_pool":["Alpha","Beta"]}
id = <derived per NIP-01: sha256([0, pubkey, created_at, kind, tags, content])>
sig = <BIP-340 Schnorr signature with aux=0x00…00>
{"display_name":"Test Agent","system_prompt":"You are an updated test assistant.","avatar_url":"https://example.com/avatar.png","runtime":"goose","model":"claude-opus-4","provider":"anthropic","name_pool":["Alpha","Beta","Gamma"]}
content = {"display_name":"Test Agent","system_prompt":"You are an updated test assistant.","avatar_url":"https://example.com/avatar.png","runtime":"goose","model":"claude-opus-4","provider":"anthropic","name_pool":["Alpha","Beta","Gamma"]}
id = <derived per NIP-01>
sig = <BIP-340 Schnorr signature with aux=0x00…00>
```
After Event 3, the head for slug `test-agent` is Event 3 (greatest `created_at`). Event 1 is superseded.
### Head selection with tiebreak
If two events share `created_at = 1700000000` and slug `test-agent`, the head is the event with the lexicographically lowest `id` (hex comparison per NIP-01).
### Implementation notes
Unlike [NIP-AE](NIP-AE.md), persona events involve no encryption, no HMAC derivation, and no conversation key. The test vectors are standard NIP-33 events with JSON content — implementations need only:
