Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add AfterRealm/father-time/plugin install father-timeWrote 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/afterrealm/father-time/session-health)<a href="https://agentmods.dev/skills/afterrealm/father-time/session-health"><img src="https://agentmods.dev/badge/skills/afterrealm/father-time/session-health/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/afterrealm/father-time/session-health"><img src="https://agentmods.dev/badge/skills/afterrealm/father-time/session-health.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 | $0.00067 | $0.01174 |
| Opus 5 | $0.00034 | $0.00587 |
| Sonnet 5 | $0.00013 | $0.00235 |
| Haiku 4.5 | $0.00007 | $0.00117 |
Grade A, and why
session-health scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 12d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 120 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Session Health Check
Show the user real session health data — not estimates. Parse actual token counts from the JSONL transcript.
How to Get Real Data
For current session only:
python "${CLAUDE_PLUGIN_ROOT}/scripts/session_health.py" --current
For all sessions:
python "${CLAUDE_PLUGIN_ROOT}/scripts/session_health.py"
For a specific project:
python "${CLAUDE_PLUGIN_ROOT}/scripts/session_health.py" "project-name-fragment"
When invoked directly (not via time-menu), ask the user first with AskUserQuestion: Question: "Which sessions?" Header: "Health" Options:
- Label: "Current Session" Description: "Just this session"
- Label: "All Sessions" Description: "All active projects"
To override the compaction threshold (default 1M):
python "${CLAUDE_PLUGIN_ROOT}/scripts/session_health.py" --threshold 800000
Combined:
python "${CLAUDE_PLUGIN_ROOT}/scripts/session_health.py" --threshold 800000 "project-name-fragment"
For structured output (programmatic consumption — preferred when you need to extract specific fields rather than display them):
python "${CLAUDE_PLUGIN_ROOT}/scripts/session_health.py" --format json --current
Run python "${CLAUDE_PLUGIN_ROOT}/scripts/session_health.py" --help for the full flag and exit-code reference.
The script parses JSONL transcripts and reads actual usage blocks from API responses to get:
- Real context usage —
input_tokens + cache_read_input_tokens + cache_creation_input_tokensfrom the last assistant turn = actual context window size - JSONL file size — total transcript weight
- Compaction count — how many
compact_boundarymarkers exist - Turn count — total assistant responses
- Cache efficiency — cache read vs write tokens
- Total tokens — cumulative input and output across the session
How Context Is Calculated
The JSONL contains usage data on every assistant message:
"usage": {
"input_tokens": 42,
"output_tokens": 1500,
"cache_read_input_tokens": 450000,
"cache_creation_input_tokens": 2000
}
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.
- 12d ago First seen · 120 lines · 67 tokens per session scan A d1ae1ebc435d
session-health is a skill published in the GitHub repository AfterRealm/father-time (6 stars, last pushed 4mo ago), licensed MIT. It adds 67 tokens to every session and 1,174 once invoked, about $0.0003 per session on Opus 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 2026-08-31.
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