Limits and Sizes

● Intermediate5 min

Every limit and size in Kavach in one place: number ranges, text, lists, tasks, the network, JSON, AI calls, the GPU and files, each linked to the page that explains it.

Each table is the same one its topic's page shows, from one list, so the two always agree.

Numbers

What	Limit or size	Source
`Int`	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 (64 bits); going past it panics	01-built-in-types.md
`Int8, Int16, Int32`	-128 to 127; -32,768 to 32,767; -2,147,483,648 to 2,147,483,647	01-built-in-types.md
`UInt8, UInt16, UInt32, UInt64`	0 to 255; 0 to 65,535; 0 to 4,294,967,295; 0 to 18,446,744,073,709,551,615	01-built-in-types.md
`Float`	64 bits: about 15 to 17 significant digits, up to about 1.8e308	01-built-in-types.md
`Float32`	32 bits: about 7 significant digits, up to about 3.4e38	01-built-in-types.md
`Decimal`	no limit: up to about 38 digits in a fast 128-bit form, more in a bigger one; a division that doesn't end keeps 18 digits after the point	01-built-in-types.md
`BigInt`	no limit: as many digits as the number needs	01-built-in-types.md

Explained on Data Types

Text

What	Limit or size	Source
`String`	UTF-8 text, as long as memory allows; it can't be changed in place	01-built-in-types.md
`s.len()`	counts characters, not bytes: "नमस्ते".len() is 6	02-built-in-methods.md
`Char`	one Unicode character: code points 0 to 0x10FFFF, surrogates excluded	01-built-in-types.md

Explained on Strings

Lists

What	Limit or size	Source
`[UInt8], [Int8], [Bool]`	1 byte per item	0030-byte-packed-lists.md
`[Int16], [UInt16]; [Int32], [UInt32], [Float32]`	2 bytes; 4 bytes per item	0045-packed-lists-of-small-numbers.md
`Other items`	8 bytes per item: a 64-bit number, or a reference to a bigger value. Packing is in native code; the interpreter keeps its own values	0045-packed-lists-of-small-numbers.md

Explained on Lists

Tasks and channels

What	Limit or size	Source
`Channel capacity`	1 or more; put waits while the channel is full	09-concurrency.md
`A task's stack`	512 MB of address space each, used only as calls need it	lib.rs

Explained on Channels

Network

What	Limit or size	Source
`Any network wait (not accept or receive)`	gives up after 30 seconds, with TimedOut; .timeout(d) changes it	10-net.md
`conn.read()`	at most 64 KB at a time	10-net.md
`A UDP datagram`	at most 64 KB is read	10-net.md
`An HTTP server's idle connection`	closed after 5 seconds without a request	11-http.md

Explained on Sockets

JSON

What	Limit or size	Source
`Nesting`	128 levels deep; max_depth raises it, up to 10,000	12-json.md
`Text`	64 MB; max_bytes raises it	12-json.md
`Fields in one object`	100,000; max_fields raises it	12-json.md
`A number's exponent`	from 10^-10,000 to 10^10,000, for decimal() and bigint()	12-json.md

Explained on JSON

Random numbers

What	Limit or size	Source
`random.bytes(n)`	n from 0 to 65,536 per call	15-random.md

Explained on Random Numbers

Logging

What	Limit or size	Source
`A log file`	a new file after 10 MB (max_bytes); 5 older ones kept (keep)	12-log.md
`Events waiting for an OpenTelemetry collector`	up to 10,000, sent at least once a second; at exit, up to 2 seconds to send the rest	12-log.md

Explained on Logging

AI calls

What	Limit or size	Source
`The model`	claude-haiku-5-5, unless the agent (model) or the call (model:) chooses one	04-typed-ai-calls.md
`An answer's length`	4,096 tokens, reasoning included; a Model's max_tokens changes it	04-typed-ai-calls.md
`An answer that doesn't fit the type`	asked again 2 times, then InvalidOutput	04-typed-ai-calls.md

Explained on ask<T>

GPU

What	Limit or size	Source
`Values in a gpu fn`	Float32, Int32, UInt32 and Bool only	15-gpu.md
`A record or tuple item`	1 to 8 fields of those types	15-gpu.md

Explained on GPU: gpu fn

Files and functions

What	Limit or size	Source
`A .kav file`	500 lines, counting every line: an error by default	12-maintainability.md
`A function body`	80 lines: a warning	12-maintainability.md

Explained on Small Files

Recursion

How deep a function can call itself depends on where it runs: see the table on Recursion.

Limits that a setting can change, such as the file length, are listed with their settings on Settings.