Nebula MCP Tools: Complete Reference for All 23 Tools

Nebula exposes 23 MCP tools that give your AI agent a full Stellar blockchain wallet with payments, yield, spending controls, and on-chain identity. Every tool is invoked directly from your agent’s chat interface — just say “Use <tool_name> from Nebula”. No code required. The sections below document every tool’s parameters, behavior, spending-limit status, and an example chat prompt you can paste directly.

All 23 tools at a glance

Tool	Category	Subject to spending limits?
`ping`	Wallet	No
`help`	Wallet	No
`get_address`	Wallet	No
`check_balance`	Wallet	No
`wallet_dashboard`	Wallet	No
`request_funding`	Wallet	No
`transfer_xlm`	Transfers	Yes
`transfer_usdc`	Transfers	Yes
`spending_report`	Spending limits	No
`deploy_policy`	On-chain policy	No
`get_policy_status`	On-chain policy	No
`set_policy_limits`	On-chain policy	No
`x402_fetch`	x402 payments	Yes
`mpp_open_session`	MPP sessions	Yes (budget)
`mpp_status`	MPP sessions	No
`mpp_fetch`	MPP sessions	Against session budget
`mpp_close_session`	MPP sessions	No
`get_treasury_status`	Treasury	No
`set_liquidity_threshold`	Treasury	No
`optimize_treasury`	Treasury	No
`blend_check_rates`	Treasury	No
`register_identity`	Agent identity	No
`get_my_reputation`	Agent identity	No

Wallet & dashboard

These six tools cover the core wallet lifecycle: connectivity checks, balance queries, and funding your agent.

Tool	Parameters	What it does	Limits?
`ping`	—	Health check — confirms the Nebula MCP server is running and returns the current timestamp.	No
`help`	`category?` (string)	Full feature guide for all tools by category, environment variables, quick-start prompts, and your current config status.	No
`get_address`	—	Returns the wallet public key (`G...`) for the configured `STELLAR_SECRET_KEY`.	No
`check_balance`	—	Returns XLM and USDC balances for the wallet on the configured network.	No
`wallet_dashboard`	—	Renders an interactive in-chat UI (MCP Apps) showing balances, spending limits, treasury status, active MPP session, and 8004 identity.	No
`request_funding`	—	Returns a Friendbot link on testnet, or manual funding instructions on mainnet.	No

help parameter details

Transfers

Send XLM or USDC to any Stellar address. Both tools are checked against your spending limits before the transaction signs.

Tool	Parameters	What it does	Limits?
`transfer_xlm`	`destination` (string), `amount` (string)	Sends XLM to a Stellar address on the configured network.	Yes
`transfer_usdc`	`destination` (string), `amount` (string)	Sends USDC to a Stellar address. Requires a USDC trustline on the destination account.	Yes

transfer_xlm / transfer_usdc parameter details

destination

string

required

Recipient Stellar public address starting with G.

amount

string

required

Amount to send as a decimal string, e.g. "1.5" for XLM or "0.50" for USDC.

Both transfer tools check your per-call cap (MAX_PER_CALL) and rolling 24-hour cap (MAX_PER_DAY) before signing. If either limit would be exceeded, the transfer is blocked and the reason is returned.

Example prompts

Use transfer_xlm from Nebula with destination GABCDE...XYZ and amount 5
Use transfer_usdc from Nebula with destination GABCDE...XYZ and amount 0.50

Spending limits

spending_report

Tool	Parameters	What it does	Limits?
`spending_report`	—	Returns the per-call cap, daily cap, amount spent in the rolling 24-hour window, any active MPP session reserved amount, and remaining budget. When `POLICY_CONTRACT_ID` is set, reads the on-chain policy instead of the off-chain env vars.	No

Use spending_report any time you want to know how much budget your agent has consumed and what headroom remains.Example prompt

Use spending_report from Nebula

On-chain policy (Soroban)

Deploy a Soroban smart contract to enforce spending limits at the blockchain level. Once a POLICY_CONTRACT_ID is set, it overrides the off-chain MAX_PER_CALL and MAX_PER_DAY environment variables and creates an immutable on-chain audit trail.

Tool	Parameters	What it does	Limits?
`deploy_policy`	`max_per_call?` (string), `max_per_day?` (string)	Deploys and initializes a new `nebula-policy` Soroban contract using the bundled WASM. Returns the `POLICY_CONTRACT_ID` to add to your MCP env.	No
`get_policy_status`	—	Reads the on-chain limits and rolling-window usage from the policy contract. Requires `POLICY_CONTRACT_ID` to be set.	No
`set_policy_limits`	`max_per_call` (string), `max_per_day` (string)	Updates per-call and daily caps on the existing policy contract (owner only, no redeploy needed).	No

deploy_policy parameter details

max_per_call

string

Initial per-call spending limit. Defaults to the MAX_PER_CALL environment variable if omitted.

max_per_day

string

Initial rolling 24-hour spending limit. Defaults to the MAX_PER_DAY environment variable if omitted.

set_policy_limits parameter details

max_per_call

string

required

New per-call limit in XLM/USDC units, e.g. "10".

max_per_day

string

required

New rolling 24-hour daily limit, e.g. "50".

After running deploy_policy, copy the returned contract ID into your MCP config as POLICY_CONTRACT_ID. From that point on, MAX_PER_CALL and MAX_PER_DAY env vars are ignored for enforcement.

Example prompts

Use deploy_policy from Nebula with max_per_call 10 and max_per_day 50
Use get_policy_status from Nebula
Use set_policy_limits from Nebula with max_per_call 20 and max_per_day 100

x402 payments

Your agent can autonomously pay for HTTP APIs that return a 402 Payment Required response with USDC via the x402 protocol — no human intervention needed.

Tool	Parameters	What it does	Limits?
`x402_fetch`	`url` (string)	GETs a URL. On HTTP 402, parses the payment terms, pays USDC automatically, and retries the request with the payment header. Subject to spending limits.	Yes

x402_fetch parameter details

url

string

required

The URL to fetch. Must be a valid HTTP or HTTPS URL. The tool handles the full request → 402 → pay → retry flow automatically.

x402 payments count against your MAX_PER_CALL and MAX_PER_DAY limits just like direct transfers. Use spending_report to check remaining budget before making a series of paid API calls.

Example prompt

Use x402_fetch from Nebula with url https://api.example.com/premium-data

MPP sessions (streaming / high-frequency)

MPP (Micro-Payment Protocol) sessions let your agent make many micro-payments with a single on-chain deposit, settling everything in one final transaction. This is ideal for high-frequency API calls where per-request on-chain transactions would be too slow or expensive. Typical flow: mpp_open_session → mpp_fetch (repeat as needed) → mpp_close_session

Tool	Parameters	What it does	Limits?
`mpp_open_session`	`budget` (string), `recipient?` (string)	Deploys a one-way payment channel Soroban contract and deposits the session budget on-chain. The budget counts against spending limits.	Yes (budget)
`mpp_status`	—	Returns the active session’s channel address, total budget, committed spend so far, and remaining balance.	No
`mpp_fetch`	`url` (string)	Fetches an MPP-gated URL using off-chain signed commitments — no per-request on-chain transaction. Rejects payments that would exceed session budget.	Against session budget
`mpp_close_session`	—	Settles the session on-chain: pays the accumulated committed amount to the recipient and refunds any unused deposit.	No

mpp_open_session parameter details

budget

string

required

Total session budget in USDC, e.g. "1.0". This amount is deposited on-chain immediately and counted against MAX_PER_CALL and MAX_PER_DAY.

recipient

string

Recipient Stellar public address (G...) for channel payouts. Defaults to the MPP_RECIPIENT environment variable.

mpp_fetch parameter details

url

string

required

MPP channel-gated URL to fetch. Payments are made via off-chain cumulative commitments — no on-chain transaction per call.

Only one MPP session can be active at a time. Call mpp_close_session before opening a new one.

Example prompts

Use mpp_open_session from Nebula with budget 1.0 and recipient GABCDE...XYZ
Use mpp_status from Nebula
Use mpp_fetch from Nebula with url https://stream.example.com/data
Use mpp_close_session from Nebula

Treasury & yield (Blend)

Nebula’s background rebalancer automatically moves idle funds into Blend lending pools to earn yield, withdrawing when your liquid balance drops below a threshold. The tools below let you inspect and control that process.

Tool	Parameters	What it does	Limits?
`get_treasury_status`	—	Shows liquid balance, Blend deposit amount, supply APY, liquidity threshold, rebalance interval, and last rebalance details.	No
`set_liquidity_threshold`	`threshold` (string)	Sets the minimum liquid balance. Funds above this threshold are auto-deposited to Blend on the next rebalance cycle.	No
`optimize_treasury`	—	Triggers a single rebalance immediately (deposit excess or withdraw to threshold), without waiting for the next automatic cycle.	No
`blend_check_rates`	—	Returns the current Blend supply APY rates on testnet (read-only, no transaction).	No

set_liquidity_threshold parameter details

threshold

string

required

Minimum liquid balance to keep on hand, e.g. "10" for 10 XLM. Funds above this level are eligible for Blend deposit.

Treasury rebalancing is not subject to agent spending limits. TREASURY_MAX_PER_REBALANCE is a separate cap that limits how much the rebalancer can move in a single transaction.

Example prompts

Use get_treasury_status from Nebula
Use set_liquidity_threshold from Nebula with threshold 20
Use optimize_treasury from Nebula
Use blend_check_rates from Nebula

Agent identity (Stellar8004)

Tool	Parameters	What it does	Limits?
`register_identity`	—	Mints an ERC-8004 agent NFT for this wallet using the Stellar8004 contracts. Idempotent — safe to call even if already registered.	No
`get_my_reputation`	—	Returns this agent’s feedback count, average score, and number of unique clients from the on-chain reputation registry.	No

Use AGENT8004_NAME, AGENT8004_DESCRIPTION, and AGENT8004_IMAGE_URL environment variables to set your agent’s display metadata before calling register_identity.

Example prompts

Use register_identity from Nebula
Use get_my_reputation from Nebula

​All 23 tools at a glance

​Wallet & dashboard

​Transfers

​Spending limits

​On-chain policy (Soroban)

​x402 payments

​MPP sessions (streaming / high-frequency)

​Treasury & yield (Blend)

​Agent identity (Stellar8004)

All 23 tools at a glance

Wallet & dashboard

Transfers

Spending limits

On-chain policy (Soroban)

x402 payments

MPP sessions (streaming / high-frequency)

Treasury & yield (Blend)

Agent identity (Stellar8004)