Fhir Search Spec

What it does

When your agent uses it

• The user needs to look up
• Understand FHIR search behaviour — search parameter types (string
• Search prefixes (eq
• Search modifiers (:exact

Example prompts

• “s type or FHIRPath expression, or answering”
• “/fhir-search-spec”

Workflow steps

2 steps, taken from the first numbered list in SKILL.md.

1. 1FHIR Search Specification — references/FHIR_search.md (very large). The normative HL7
2. 2SearchParameter Registry — references/search-parameters.json. A FHIR Bundle containing

What it can do on your machine

Read from SKILL.md and the folder at commit 56a3b4a. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • jq

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Fhir Search Spec loads about 649 tokens when it runs, and up to ~573k if it reads all its reference files. Until then it costs about 210 tokens; SKILL.md has 172 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~210

When it runs · the whole SKILL.md, loaded when a task matches

~649

With references · SKILL.md plus every file in references/, read only if the agent opens them

~573k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from aehrc/pathling at commit 56a3b4a, republished under its Apache-2.0 licence (© aehrc). 172 words, ~649 tokens.

name

fhir-search-spec

description

FHIR RESTful search specification expert with access to the official HL7 search specification text and the formal SearchParameter registry. Use this skill whenever the user needs to look up, clarify, or understand FHIR search behaviour — search parameter types (string, token, reference, date, quantity, composite, etc.), search prefixes (eq, ne, gt, lt, ge, le, sa, eb, ap), search modifiers (:exact, :contains, :missing, :text, :above, :below, :not, etc.), chaining, reverse chaining (_has), includes (_include, _revinclude), or the standard SearchParameter definitions for a given resource type. Trigger this skill when implementing or reviewing FHIR search behaviour, resolving ambiguity about a search parameter's type or FHIRPath expression, or answering "what does the spec say about X search behaviour?" questions.

REGISTRY=.claude/skills/fhir-search-spec/references/search-parameters.json

# Find all string search parameters for Patient
jq '.entry[].resource | select(.base[]? == "Patient" and .type == "string") | {code, expression, description}' "$REGISTRY"

# Find a specific search parameter by code
jq '.entry[].resource | select(.code == "name") | {code, base, type, expression}' "$REGISTRY"

© aehrc, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 2 other files (references) in .claude/skills/fhir-search-spec of aehrc/pathling.

• SKILL.md
• references/FHIR_search.md
• references/search-parameters.json

Open the folder on GitHubat commit 56a3b4a