Tools & discovery
Toolkits, tools, and the search → schema → execute loop.
Stacklink exposes hundreds of provider operations without flooding your model's context. The trick is discovery: the agent searches for what it needs, fetches the exact schema, then executes.
Toolkits and tools
A toolkit is a provider (Zoho Books, Razorpay, Gmail, …). A tool is one model-callable operation inside it. Every tool carries metadata the agent and the platform rely on:
| Field | Meaning |
|---|---|
key | Stable identifier, e.g. zoho_books.invoices.create_invoice. |
capability | Logical grouping, e.g. invoices.write. |
mutationLevel | none (read), write, or destructive. |
inputSchema / outputSchema | JSON Schema the model fills and receives. |
searchDescriptor | Intent, tags, and examples that power semantic search. |
The discovery loop
Search by intent
STACKLINK_SEARCH_TOOLS ranks tools against a natural-language query (or several). The agent never
hardcodes keys.
Fetch exact schemas
STACKLINK_GET_TOOL_SCHEMAS returns the precise input/output schema for the chosen tools — so the
model fills arguments correctly the first time.
Execute
STACKLINK_EXECUTE_TOOL runs one tool; STACKLINK_MULTI_EXECUTE_TOOL runs a batch in parallel or
sequentially with concurrency control.
const { tools } = await session.searchTools({ query: 'refund a payment' });
const schemas = await session.getToolSchemas([tools[0].key]);
const result = await session.executeTool({ toolKey: tools[0].key, input: { /* ... */ } });Why not just expose every tool?
Some providers expose 500+ operations (Zoho Books alone has ~574). Mounting them all would blow past context limits and confuse the model. Discovery keeps the active toolset small and relevant, and lets one set of meta-tools serve every provider.
Caching
Tool search, schemas, and toolkit listings are cached (client- and server-side) because they change infrequently. Discovery responses can be bypassed with a cache control flag when you need freshly-reconciled results — for example right after enabling a new provider.
Direct execution
You don't have to go through meta-tools. The HTTP API and SDK expose /v1/tools/search,
/v1/tools/schemas, /v1/tools/execute, and /v1/tools/execute-batch directly, plus session-scoped
variants. The meta-tools are simply these same operations packaged as model-callable tools.
Search and run 400+ tools, free
Every search, schema fetch, and tool run is a standard op — and the free plan includes 20,000 a month, hard-capped.