Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add ksachdeva/zephyr-rtos-ai --skill zephyr-jsongit clone --depth 1 https://github.com/ksachdeva/zephyr-rtos-aiWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/ksachdeva/zephyr-rtos-ai/zephyr-json)<a href="https://agentmods.dev/skills/ksachdeva/zephyr-rtos-ai/zephyr-json"><img src="https://agentmods.dev/badge/skills/ksachdeva/zephyr-rtos-ai/zephyr-json/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/ksachdeva/zephyr-rtos-ai/zephyr-json"><img src="https://agentmods.dev/badge/skills/ksachdeva/zephyr-rtos-ai/zephyr-json.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00068 | $0.01535 |
| Opus 5.5 | $0.00027 | $0.00614 |
| Sonnet 5.5 | $0.00014 | $0.00307 |
| Haiku 4.5 | $0.00007 | $0.00153 |
Grade A, and why
zephyr-json scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 182 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Zephyr JSON
Zephyr's JSON library provides compile-time descriptor-based serialization without dynamic memory allocation. It maps C struct fields to JSON keys using static descriptors.
Quick Start
#include <zephyr/data/json.h>
// 1. Define your data structure
struct sensor_data {
const char *device_id;
int32_t temperature;
bool active;
};
// 2. Create descriptors mapping struct fields to JSON keys
static const struct json_obj_descr sensor_descr[] = {
JSON_OBJ_DESCR_PRIM(struct sensor_data, device_id, JSON_TOK_STRING),
JSON_OBJ_DESCR_PRIM(struct sensor_data, temperature, JSON_TOK_NUMBER),
JSON_OBJ_DESCR_PRIM(struct sensor_data, active, JSON_TOK_TRUE),
};
// 3. Encode to JSON
struct sensor_data data = {.device_id = "sensor-01", .temperature = 25, .active = true};
char buffer[128];
int ret = json_obj_encode_buf(sensor_descr, ARRAY_SIZE(sensor_descr), &data, buffer, sizeof(buffer));
// buffer: {"device_id":"sensor-01","temperature":25,"active":true}
// 4. Decode from JSON
char json[] = "{\"device_id\":\"sensor-02\",\"temperature\":30,\"active\":false}";
struct sensor_data parsed;
int64_t result = json_obj_parse(json, strlen(json), sensor_descr, ARRAY_SIZE(sensor_descr), &parsed);
Kconfig
# Required
CONFIG_JSON_LIBRARY=y
# Optional: Enable float/double support (requires full libc)
CONFIG_JSON_LIBRARY_FP_SUPPORT=y
Token Types Quick Reference
| Token Type | C Type | JSON Type |
|---|---|---|
JSON_TOK_STRING |
const char * |
"string" |
JSON_TOK_STRING_BUF |
char[] |
"string" (copies to buffer) |
JSON_TOK_NUMBER |
int32_t |
42 |
JSON_TOK_INT |
int8_t, int16_t |
-128 |
JSON_TOK_UINT |
uint8_t, uint16_t, uint32_t |
255 |
JSON_TOK_INT64 |
int64_t |
9223372036854775807 |
JSON_TOK_UINT64 |
uint64_t |
18446744073709551615 |
JSON_TOK_TRUE / JSON_TOK_FALSE |
bool |
true/false |
JSON_TOK_FLOAT_FP |
float |
3.14 (requires FP_SUPPORT) |
JSON_TOK_DOUBLE_FP |
double |
3.14159 (requires FP_SUPPORT) |
JSON_TOK_OBJECT_START |
nested struct | {...} |
JSON_TOK_ARRAY_START |
array | [...] |
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 182 lines · 68 tokens per session scan A c66f48e13555
zephyr-json is a skill published in the GitHub repository ksachdeva/zephyr-rtos-ai (23 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 68 tokens to every session and 1,535 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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