HTTP and process

Use this when making HTTP requests, spawning child processes, or wiring external endpoints as typed ilo functions.

HTTP and process-spawn builtins require the native binary. They are not available in the npm/WASM build.

Builtins

Function	Signature	Description	Example
get	t > R t t	HTTP GET (returns Result)	get "https://..."
get	t M > R t t	HTTP GET with headers	get url headers
pst	t t > R t t	HTTP POST (url, body). Renamed from post in 0.12.0	pst url body
pst	t t M > R t t	HTTP POST with headers	pst url body headers
run	t L > R (M t t) t	Spawn cmd with argv list. No shell, no glob.	run "git" ["status"]
$	t L > R (M t t) t	run shorthand (sugar for run)	$"git" ["status"]
env	t > R t t	Read environment variable	env "API_KEY"

In 0.12.0 the $ sigil was rebound from HTTP get (parochial — $ for HTTP is unique to ilo) to the new run builtin (argv-list process spawn). $cmd argv compiles to run cmd argv. HTTP get is still called by name.

post was renamed to pst to bring it into line with the I/O compression family (rd, wr, srt, flt, fld, fmt). The old name no longer resolves; the verifier surfaces a did-you-mean hint pointing at pst.

Process spawn

run cmd argv is the only process-spawn primitive. The first argument is the program (text), the second is the argv list (L t), and the result is a Result whose Ok carries a three-key Map of stdout / stderr / code as text.

ilo

r=run "echo" ["hi"]
-- Ok({"stdout":"hi\n","stderr":"","code":"0"})

$"git" ["status" "--short"]
-- equivalent: $ is the sigil shortcut for run

No shell, no interpolation, no glob. The argv list is passed directly to std::process::Command::args. There is no sh -c, no string concatenation between cmd and argv, and no glob expansion. This is the principled defence against shell injection.

Non-zero exit is NOT an error. Err is reserved for spawn failures (command not found, permission denied, output cap exceeded). A child that returns a non-zero exit code surfaces as Ok({"stdout":..., "stderr":..., "code":"<n>"}); the caller inspects code and branches.

Captured output is capped at 10 MiB per stream. Either stream exceeding the cap returns an Err rather than partial capture.

Inherits parent env + cwd. No override knobs in v1. Stdin is /dev/null.

Example

ilo

fetch url:t>R t t;get url

Auto-unwrap with ! propagates errors automatically:

ilo

f url:t>R t t;r=get! url;~r

See Error Handling for full details on ! and Result types.

HTTP tools (typed endpoints)

Tool declarations let you wire external HTTP endpoints as typed ilo functions. Create a tools.json file:

JSON

{
  "tools": {
    "weather": {
      "url": "https://api.example.com/weather"
    },
    "lookup": {
      "url": "https://api.example.com/lookup"
    }
  }
}

Each key is the tool name. The value must include a url field.

Shell

ilo --tools tools.json 'get-weather city:t>R t t;weather city' "London"

Tools are type-checked at load time, the agent cannot call a tool with the wrong parameter types.

See also Tools for MCP integration.