# set_webhook

Register a webhook that fires when market conditions meet your criteria. Fathom evaluates conditions every 60 seconds and POSTs a JSON payload to your URL when all conditions are met. Example: alert me at my bot URL when fear_greed < 20 and regime == capitulation. Available fields: fear_greed, risk_score, opportunity_score, regime, posture, cycle_phase, tvl_change_7d, defi_health, macro_impact, net_flow_signal, leverage_signal, btc_put_call, btc_sp500_correlation, macro_risk_appetite.

Agent View of the PolicyLayer registry record for `set_webhook`. HTML page: https://policylayer.com/tools/0xhashy-fathom-fyi/set-webhook

## Facts

- Tool: `set_webhook`
- Server: Fathom Fyi (`0xhashy/fathom-fyi`) — https://policylayer.com/tools/0xhashy-fathom-fyi.md
- Homepage: https://github.com/0xHashy/fathom-fyi
- Risk category: Write (Medium risk)
- Registry record: grade C, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "set_webhook",
    "arguments": {}
  }
}
```

## Why set_webhook is rated Medium

This is a Write operation because it creates and stores a new webhook configuration in the Fathom system. While webhooks are a standard integration pattern, the tool persists state (a webhook rule) that can trigger automated downstream actions.

From the tool's own definition: "Tool registers (creates) a webhook endpoint by POSTing a JSON payload to a user-specified URL. The description explicitly states 'Register a webhook' and 'POSTs a JSON payload to your URL', indicating creation of a persistent notification mechanism."

Risk signals: Bulk/mass operation — affects multiple targets

## Use case

AI agents use set_webhook to create or update resources in Fathom Fyi, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Fathom Fyi environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Fathom Fyi:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_webhook": {
      "limits": [
        {
          "counter": "set_webhook_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Fathom Fyi (31)

- `evaluate_strategy` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/evaluate-strategy.md
- `get_account_status` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-account-status.md
- `get_alerts` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-alerts.md
- `get_alternative_signals` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-alternative-signals.md
- `get_asset_context` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-asset-context.md
- `get_asset_momentum` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-asset-momentum.md
- `get_chain_context` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-chain-context.md
- `get_correlation_matrix` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-correlation-matrix.md
- `get_crowd_intelligence` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-crowd-intelligence.md
- `get_defi_health` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-defi-health.md
- `get_derivatives_context` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-derivatives-context.md
- `get_event_catalyst_timeline` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-event-catalyst-timeline.md
- `get_historical_context` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-historical-context.md
- `get_macro_context` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-macro-context.md
- `get_market_regime` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-market-regime.md
- `get_narrative_pulse` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-narrative-pulse.md
- `get_onchain_pulse` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-onchain-pulse.md
- `get_portfolio_analysis` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-portfolio-analysis.md
- `get_question_context` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-question-context.md
- `get_reality_check` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-reality-check.md
- `get_sentiment_state` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-sentiment-state.md
- `get_signal_history` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-signal-history.md
- `get_stablecoin_flows` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-stablecoin-flows.md
- `get_temporal_context` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-temporal-context.md
- `get_watchlist_report` — Read — https://policylayer.com/tools/0xhashy-fathom-fyi/get-watchlist-report.md
- `manage_webhooks` — Write — https://policylayer.com/tools/0xhashy-fathom-fyi/manage-webhooks.md
- `rotate_api_key` — Write — https://policylayer.com/tools/0xhashy-fathom-fyi/rotate-api-key.md
- `set_alert` — Write — https://policylayer.com/tools/0xhashy-fathom-fyi/set-alert.md
- `set_custom_strategy` — Write — https://policylayer.com/tools/0xhashy-fathom-fyi/set-custom-strategy.md
- `set_portfolio_context` — Write — https://policylayer.com/tools/0xhashy-fathom-fyi/set-portfolio-context.md
- …and 1 more: https://policylayer.com/tools/0xhashy-fathom-fyi.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=0xhashy-fathom-fyi · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/0xhashy-fathom-fyi