Tool reference
Every instrument the agent can reach for, with exactly what each one needs. Required inputs are enforced before anything costs a judgement call or execution — a missing field fails free with the fix spelled out.
Reference: dr-nib/backend/src/tools/executor.js, dr-nib/backend/src/agent/loop.js (REQUIRED_INPUTS), dr-nib/backend/src/spend/.
Research tools (free or metered, policy-approved)
| Tool | Input | Cost | Returns as evidence |
|---|---|---|---|
web_search | query (full question or keywords) | metered | ranked results |
web_fetch | urls (array of https URLs) | metered | extracted documents; paywalls/bot-checks reported, never worked around |
search_sources | query | metered | evidence-graded sources |
http_request | url + optional method/headers/body | $0 | status + headers + body; HTTP 4xx/5xx (except 402) count as failures, staying retryable |
run_code | command (one shell line) or code+language | metered | stdout in an isolated ephemeral VM — RPC reads, dataset crunching, parsing. Keys never enter the sandbox |
Observations are formatted before anything reads them: short hex values gain decimal annotations (0x4a817c800 (20000000000)), KB-sized blobs collapse to placeholders, and injection patterns are quarantined as data-never-instructions with the banner kept in the audit trail.
Spend tools (JEV-judged, always)
| Tool | Input | Ceiling | Settles |
|---|---|---|---|
tip_creator | contentUrl + amount (USD) + optional recipient + title | $1 | hub tip rail: challenge → transfer → verify, receipt + tx hash. Unresolved creators fall back to the domain holding box (claimable later). API-endpoint URLs are rejected — tip creator pages, not the APIs that listed them. |
unlock_content | url of the gated page | $2 | same x402 pay, shaped as evidence (body joins the scorable set) |
pay_x402 | url + body (the endpoint’s POST input) | $2 | any x402-gated API. Price is read off the 402 challenge — never pass an amount; no readable price means refusing to sign blind |
On spend tasks the loop funnels once free evidence is banked: first a nudge naming the spend tool, then turns restricted to spend-or-finish so research converges instead of polishing forever.
Direct transfers route through the spending mandate when configured, with no silent EOA fallback. Gateway x402 flows stay EOA-bound (contracts can’t sign authorizations) under the caps above.
What the agent sells (for external agents)
Dr. Nib meters its own retrieval to any agent with USDC — payment is the authentication, zero accounts:
| Endpoint | Price | Does |
|---|---|---|
POST /v1/x402/search | $0.01 | metered search over the free bench |
POST /v1/x402/read | $0.01 | fetch + extract one page (PDFs and Office docs included) |
Both return a standard x402 challenge (402 + payment-required); Circle Gateway settles and the content comes back. Unconfigured deployments answer 501.