# LDC-Q0005 — A parameter value uses characters outside the allowed set

## What it means

Catalog queries carry placeholders for values only the caller knows, and
each value is passed alongside the query name. Before substitution, the
value travels inside a string literal, so only plain name, number, and
path characters are accepted. A space, a quote, or any other character
outside that set stops the query before anything is looked up.

Retype the value using the accepted characters and run the query again.
The query text itself stays as published in the catalog.

## Example

```run
{"argv": ["query", "producers", "--path", "$ROOT/world.json", "--param", "predicate=bad value!"], "expect": "LDC-Q0005", "files": {"world.json": "{\"artifactHash\":\"sha256:6a9091bdeb56f398762394bb3ab882a8f44d541a1dd0dfd9ea65d4e9cac99d78\",\"features\":[\"core-executable\"],\"imports\":[],\"metadata\":{},\"nodes\":[{\"contentHash\":\"sha256:65449c25ae110f10c02d875734707f013f7fcae27b6c779700c6a2eb82fd00fc\",\"id\":\"urn:law:demo:diagnostics#Applicant\",\"kind\":\"type_decl\",\"name\":\"Applicant\",\"package\":\"urn:law:demo:diagnostics\",\"typeKind\":\"entity\"},{\"contentHash\":\"sha256:b62227d3c949b697a7bad486d2cd64dcd4ddaccef32710bd994226fd43e3033e\",\"id\":\"urn:law:demo:diagnostics#resident\",\"kind\":\"symbol_decl\",\"name\":\"resident\",\"package\":\"urn:law:demo:diagnostics\",\"parameters\":[{\"id\":\"urn:law:demo:diagnostics#resident/arg/a\",\"name\":\"a\",\"type\":{\"name\":\"urn:law:demo:diagnostics#Applicant\"}}],\"relationKind\":\"institutional\",\"symbolKind\":\"relation\"}],\"package\":{\"name\":\"demo.diagnostics\",\"namespace\":\"urn:law:demo:diagnostics\",\"semanticHash\":\"sha256:0000000000000000000000000000000000000000000000000000000000000000\",\"version\":\"0.1.0\"},\"schemaVersion\":\"law.core.ir/0.2\",\"semanticHash\":\"sha256:82a883cd86acd37faec9d0502a7498490966e772c41e0c750647a60f29c53010\",\"semanticVersion\":\"0.2.4\",\"strata\":[],\"theoryHash\":\"sha256:82a883cd86acd37faec9d0502a7498490966e772c41e0c750647a60f29c53010\"}"}}
```

## Fix

```run
{"argv": ["query", "producers", "--path", "$ROOT/world.json", "--param", "predicate=urn:law:demo:diagnostics#resident", "--pkg", "demo.diagnostics"], "expect": "LDC-Q0005", "files": {"world.json": "{\"artifactHash\":\"sha256:6a9091bdeb56f398762394bb3ab882a8f44d541a1dd0dfd9ea65d4e9cac99d78\",\"features\":[\"core-executable\"],\"imports\":[],\"metadata\":{},\"nodes\":[{\"contentHash\":\"sha256:65449c25ae110f10c02d875734707f013f7fcae27b6c779700c6a2eb82fd00fc\",\"id\":\"urn:law:demo:diagnostics#Applicant\",\"kind\":\"type_decl\",\"name\":\"Applicant\",\"package\":\"urn:law:demo:diagnostics\",\"typeKind\":\"entity\"},{\"contentHash\":\"sha256:b62227d3c949b697a7bad486d2cd64dcd4ddaccef32710bd994226fd43e3033e\",\"id\":\"urn:law:demo:diagnostics#resident\",\"kind\":\"symbol_decl\",\"name\":\"resident\",\"package\":\"urn:law:demo:diagnostics\",\"parameters\":[{\"id\":\"urn:law:demo:diagnostics#resident/arg/a\",\"name\":\"a\",\"type\":{\"name\":\"urn:law:demo:diagnostics#Applicant\"}}],\"relationKind\":\"institutional\",\"symbolKind\":\"relation\"}],\"package\":{\"name\":\"demo.diagnostics\",\"namespace\":\"urn:law:demo:diagnostics\",\"semanticHash\":\"sha256:0000000000000000000000000000000000000000000000000000000000000000\",\"version\":\"0.1.0\"},\"schemaVersion\":\"law.core.ir/0.2\",\"semanticHash\":\"sha256:82a883cd86acd37faec9d0502a7498490966e772c41e0c750647a60f29c53010\",\"semanticVersion\":\"0.2.4\",\"strata\":[],\"theoryHash\":\"sha256:82a883cd86acd37faec9d0502a7498490966e772c41e0c750647a60f29c53010\"}"}}
```

## Engine message

The engine reports this in its own wording:

```text
LDC-Q0005: parameter predicate contains invalid characters.
```

## Related

- [Questions to the engine](/constructs/queries/) — how catalog queries take values.
- [LDC-Q0004](/diagnostics/LDC-Q0004/) — when a parameter value is missing entirely.