estimate-calibrator

estimate-calibrator is a skill for Claude Code from Mathews-Tom/armory. It costs 71 tokens per session (1,736 once invoked), scanned A, original, MIT.

A skill for estimating work with best-case, likely, and worst-case time ranges, confidence levels, and stated unknowns.

In plain words
What is it for?
Use it to estimate a feature or project after breaking the work into small tasks and recording the technical and organizational assumptions.
Why use it?
It exposes uncertainty instead of hiding it inside one precise-looking estimate.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the armory plugin — 85 skills shipped together

Good fit Use it to estimate a feature or project after breaking the work into small tasks and recording the technical and organizational assumptions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mathews-tom/armory/estimate-calibrator
Install

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.

Any agent
npx skills add Mathews-Tom/armory --skill estimate-calibrator
Clone the repo
git clone --depth 1 https://github.com/Mathews-Tom/armory

Made for: Claude Code.

Or install armory, the plugin that ships this one along with the rest of its 85 skills.

Wrote 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.

agentmods badge for estimate-calibrator

README.md
[![agentmods](https://agentmods.dev/badge/skills/mathews-tom/armory/estimate-calibrator/github.svg)](https://agentmods.dev/skills/mathews-tom/armory/estimate-calibrator)
Your own site
<a href="https://agentmods.dev/skills/mathews-tom/armory/estimate-calibrator"><img src="https://agentmods.dev/badge/skills/mathews-tom/armory/estimate-calibrator/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.

agentmods 80×15 button for estimate-calibrator

Your own site · 80×15
<a href="https://agentmods.dev/skills/mathews-tom/armory/estimate-calibrator"><img src="https://agentmods.dev/badge/skills/mathews-tom/armory/estimate-calibrator.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 71 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,736 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Prompt Injection · line 152
    Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.
    Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00071 $0.01736
Opus 5 $0.00036 $0.00868
Sonnet 5 $0.00014 $0.00347
Haiku 4.5 $0.00007 $0.00174

Measured 9d ago against content hash 8fa90d730539, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

estimate-calibrator 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 9d 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.

skills/estimate-calibrator/SKILL.md · 168 lines

How it starts

The opening of the file, as written. The whole thing — 168 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Estimate Calibrator

Replaces single-point guesses with structured three-point estimates: decomposes work into atomic units, estimates best/likely/worst case for each, identifies unknowns and assumptions, calculates aggregate ranges using PERT, and assigns confidence levels with explicit rationale.

Reference Files

File Contents Load When
references/estimation-methods.md PERT formula, three-point estimation, Monte Carlo basics Always
references/unknown-categories.md Technical, scope, external, and organizational uncertainty types Unknown identification
references/calibration-tips.md Cognitive biases in estimation, historical calibration, buffer strategies Always
references/sizing-heuristics.md Common task size patterns, complexity indicators, reference class data Quick sizing needed

Prerequisites

  • Work item description (feature, task, project)
  • Decomposed tasks (or use task-decomposer skill first)
  • Context: team familiarity, tech stack, existing codebase

Workflow

Phase 1: Decompose Work

If the work item is not already decomposed into atomic units:

  1. Break into tasks — Each task should be estimable independently.
  2. Right granularity — Tasks should be 1 hour to 3 days. Larger tasks have higher uncertainty; break them down further.
  3. Identify dependencies — Tasks on the critical path determine the minimum duration.

Phase 2: Three-Point Estimate

For each task, estimate three scenarios:

Scenario Definition Mindset
Best case Everything goes right. No surprises. "If I've done this exact thing before"
Likely case Normal friction. Some minor obstacles. "Realistic expectation with typical setbacks"
Worst case Significant problems. Not catastrophic. "Murphy's law but not a disaster"

Read the full file on GitHub · 168 lines

Files

What ships with it

5 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.

Changes

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.

  1. 9d ago First seen · 168 lines · 71 tokens per session scan A 8fa90d730539

Subscribe to this mod's changes

estimate-calibrator is a skill published in the GitHub repository Mathews-Tom/armory (316 stars, last pushed 3d ago), licensed MIT. It adds 71 tokens to every session and 1,736 once invoked, about $0.0004 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 2026-08-30.

Related

Other skills, from other repositories

openagentskill-registry

Discover, compare, audit, and safely install reusable AI Agent Skills with OpenAgentSkill. Use whenever an agent needs a capability it does not already have, must compare Skill alternatives, or needs evidence before installing third-party instructions.

Leon-Drq/openagentskill · 51 tokens

manager

A session-to-GitHub tracker that creates, updates, and reads issues across repositories, including their labels, parent epics, and project-board placement.

serejaris/personal-corp-os · 63 tokens

weekly-retro

A structured weekly retrospective for a one-person business run with AI agents. It gathers evidence from code, project tools, and canonical business files, then records findings and outcomes.

serejaris/personal-corp-os · 49 tokens

art-director

Orchestrate iterative visual style searches with branch prompts, decision graphs, feedback loops, and final direction selection.

serejaris/personal-corp-os · 26 tokens

html-draft

Use when user wants a standalone HTML diagram in flat engineering blueprint style — architecture diagrams, system flows, technical spec sheets, component maps. Generates one HTML file using Tailwind v4 (browser CDN) for layout and D3 v7 (CDN) for SVG diagrams. User-invoked only — do NOT auto-trigger. Triggers on…

serejaris/personal-corp-os · 130 tokens

pm-metrics

A product-metrics review aid that examines trends, unusual changes, possible causes, and recommended actions. It can organize a main product metric into lower-level measures, inspect retention and funnels, read A/B tests, and compare results with goals.

serejaris/personal-corp-os · 160 tokens