Claude's pains

[mitchpaulus]

Pain points (for you to fix)

1. Missing-comma error message is misleading. { "a": 1 "b": 2 } (no comma) reports Expected a string or literal after ':' pointing at the value after the colon, not "missing comma between entries." Cost me the most time. Compounding it: the Dictionary section of mshell.md only shows single-key literals ({ "key": 1 }); the multi-key-with-commas form only appears incidentally in the Type System section. A two-key example in the Dictionary section would fix this.
2. :type? collides with the type keyword. Bareword getters silently fail on reserved words — @att :type? gives the same misleading Expected a string or literal after ':'. I had to use :"type"?. Maybe allow keywords as bareword getter keys, or emit a clearer "reserved word — quote the key" message.
3. as casts are unchecked, and JSON numbers are the trap. I cast a field to size: int, the type-checker trusted it, but parseJson returns JSON numbers as Float — so size was 8169.0 at runtime. Then $"...{@size}..." failed with did not evaluate to a stringable value: float interpolation isn't allowed even though int interpolation is, and str/round work fine. Two rough edges there: (a) as gives false confidence, and (b) inconsistent interpolation rules between int and float.
4. Named-shape list cast looks buggy. […] as [Att] (where type Att = {…}) failed with cannot cast [{…}] to [Att({…})] — the two shapes printed identically. Casting to the equivalent anonymous shape [{…}] worked. Named shapes in list casts seem broken (or the error needs to explain what actually differs).
5. No writeFileBytes / no len on bytes. Minor, but writing an HTTP body to disk pushed me toward utf8Str (fine for ASCII CSV, wrong for real binary). A binary file-write and a byte-length builtin would round things out.