Agent skill

Market Sizing

by explorium-ai in explorium-ai/gtm-skills

Market sizing skill for Claude Code and Codex: calculate TAM/SAM for any ICP against Explorium's 150M+ company dataset using real-time firmographic and technographic filters.

MITAuto-check passedProduct & Project Management

Install Market Sizing

skills CLI
$ npx skills add explorium-ai/gtm-skills --skill market-sizing -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install explorium-ai/gtm-skills market-sizing --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/explorium-ai/gtm-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/market-sizing .claude/skills/market-sizing && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
market-sizing
GitHub stars
175
Token cost
~2.4k tokens
SKILL.md length
1,309 words
Files
1
Skills in repo
17
Repo updated
First seen
Licence
MIT

At a glance

Market sizing skill for Claude Code and Codex: calculate TAM/SAM for any ICP against Explorium's 150M+ company dataset using real-time firmographic and technographic filters.

  • Works in 7 steps: Parse the ICP into filter dimensions.… → Disambiguate ambiguous regions BEFORE… → Resolve every free-text field via… → …
  • Territory design
  • SKILL.md covers Input, Workflow, Output Format and Limitations
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Market Sizing is an agent skill from explorium-ai/gtm-skills. Market sizing skill for Claude Code and Codex: calculate TAM/SAM for any ICP against Explorium's 150M+ company dataset using real-time firmographic and technographic filters. Iteratively refines filters with the user until the account universe matches intent, then returns the count and filter set for downstream prospecting skills. Use for territory design, capacity planning, investor-ready market sizing, and ICP sharpening. Triggers on 'size the market', 'TAM for', 'how many companies match', 'is my ICP too…

Its SKILL.md is about 2.4k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Product & Project Management, covering Market sizing and Cold outreach. It works with Stripe and Snowflake. The repository describes itself as: GTM Skills for Claude & Codex. The licence is MIT.

When your agent uses it

  • Territory design
  • Capacity planning
  • Investor-ready market sizing
  • Size the market

Example prompts

  • “size the market”
  • “TAM for”
  • “how many companies match”
  • “/market-sizing”

Workflow steps

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

  1. Parse the ICP into filter dimensions. Tag each user-specified or unspecified. Persona criteria ("CTOs", "VP Sales") are recorded but NOT…
  2. Disambiguate ambiguous regions BEFORE counting. "EU" can mean European Union members or the broader European region: ask one clarifying…
  3. Resolve every free-text field via autocomplete, then classify the result into ONE of three branches before sizing.
  4. Tech-stack taxonomy-gap framing. When step 3 lands in branch (c) for a flagship vendor, document this as a coverage gap, NOT a…
  5. Size the audience. Get the total count for the resolved filter set. Country-scoped TAM caveat: the sizing endpoint does NOT strictly…
  6. Data-sparsity probe (mandatory when tech-stack or intent filters are applied). Size twice: with the filter (count_filtered) and without it…
  7. Classify the sizing band against the operative TAM.

What it can do on your machine

Read from SKILL.md and the folder at commit f0efa6b. 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

    No scripts in the folder and no shell commands in SKILL.md.

    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

Market Sizing loads about 2.4k tokens when it runs. Until then it costs about 150 tokens; SKILL.md has 1,309 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~150
When it runs · the whole SKILL.md, loaded when a task matches
~2.4k

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

Auto-check passed

The automated check found no risky patterns in SKILL.md.

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 explorium-ai/gtm-skills at commit f0efa6b, republished under its MIT licence (© explorium-ai). 1,309 words, ~2,445 tokens.

Download SKILL.mdSave it as .claude/skills/market-sizing/SKILL.md (or your agent's skills folder).
name
market-sizing
description
Market sizing skill for Claude Code and Codex: calculate TAM/SAM for any ICP against Explorium's 150M+ company dataset using real-time firmographic and technographic filters. Iteratively refines filters with the user until the account universe matches intent, then returns the count and filter set for downstream prospecting skills. Use for territory design, capacity planning, investor-ready market sizing, and ICP sharpening. Triggers on 'size the market', 'TAM for', 'how many companies match', 'is my ICP too broad', 'market sizing'. Works in Claude Code, Codex, and Hermes-Agent.

Market Sizing

Iteratively refine a company-level ICP filter set and return a count plus a structured filter artifact ready for downstream prospecting work.

Input

  • ICP description (recommended): natural language, or "my ICP" / "our ICP" / nothing (ask).
  • Use case (optional): territory design, investor sizing, ICP sharpening (default).
  • SAM hypothesis inputs (optional): addressable fraction (0 to 1) and ARPA in USD.

Workflow

  1. Parse the ICP into filter dimensions. Tag each user-specified or unspecified. Persona criteria ("CTOs", "VP Sales") are recorded but NOT applied to the company count.

  2. Disambiguate ambiguous regions BEFORE counting. "EU" can mean European Union members or the broader European region: ask one clarifying question. Same for "Americas" vs "North America" vs "US and Canada".

  3. Resolve every free-text field via autocomplete, then classify the result into ONE of three branches before sizing.

    (a) Clean canonical match. An unambiguous value is returned for the user's phrasing (e.g. "Software Development" for SaaS; "Salesforce CRM" for a Salesforce filter). Commit and proceed.

    (b) Brittle or parent-only match. The exact term does not exist in the taxonomy but a parent or sibling does (e.g. "fintech" maps only to a "Financial Services" parent; "Snowflake" only cleans up as "Snowflake Data Cloud" on a variant phrasing). STOP before sizing and surface the candidates to the user with a one-line disambiguation: "No exact match for <term>; nearest entries are <list>. Approximate with <parent>, seed a known company for a lookalike follow-up, or proceed with a tech-stack or intent proxy?" Do NOT silently substitute the parent.

    (c) No match after 2-3 variant phrasings (bare term, full product name, vendor-plus-suffix like "Stripe Payments"). Surface "no matching value" and offer the same three options as (b).

    For flagship vendors (Snowflake, Databricks, Stripe): try the suffix-qualified variant FIRST ("Snowflake Data Cloud", "Stripe Payments") because the bare token often returns a noise hit.

    Taxonomy mutex. LinkedIn industry and NAICS are mutually exclusive on a single query. Query LinkedIn FIRST; commit on a clean (branch a) match; fall through to NAICS only on no-match. Dual-querying both taxonomies in the same pass is acceptable ONLY when LinkedIn lands in the brittle branch (b) AND the user has approved looking at both candidates.

  4. Tech-stack taxonomy-gap framing. When step 3 lands in branch (c) for a flagship vendor, document this as a coverage gap, NOT a sparsity-narrow result. The skill cannot size around a tech filter with no taxonomy entry; the sparsity probe in step 6 measures something different and should not be conflated.

  5. Size the audience. Get the total count for the resolved filter set. Country-scoped TAM caveat: the sizing endpoint does NOT strictly enforce country filters at the headline-count level. For any country-scoped TAM, sum the per-location breakdown across requested ISO-2 codes. Never use the global headline count when the user asked for a specific geography.

  6. Data-sparsity probe (mandatory when tech-stack or intent filters are applied). Size twice: with the filter (count_filtered) and without it (count_unfiltered). If count_filtered / count_unfiltered is below 0.1, treat as coverage-sparse and use count_unfiltered as the operative TAM. Surface "Explorium coverage of [field] is sparse for this segment." Show both numbers.

  7. Classify the sizing band against the operative TAM.

Operative TAMBandRead
> 50,000Too broadProbably not operational.
5,000 to 50,000Healthy enterprise/mid-marketSuggest tier segmentation.
1,000 to 5,000Sweet spotFocused primary-tier list.
250 to 1,000Tight/nicheFlag capacity feasibility.
< 250Too narrowCoverage risk; suggest widening.
  1. Decide on sample accounts. Default: skip. Pull is paid; stats are free.

    Pull a ~25-row sample ONLY when ONE of these triggers fires:

    (a) User asked for account names, a quality sanity check, or a downstream list.

    (b) Sparsity probe needs noise validation. Ratio in step 6 sits near the 0.10 threshold and you cannot tell from the counts alone whether the filter is sparse-but-real or sparse-and-noisy.

    (c) Brittle match accepted in step 3. A parent-approximation or variant-qualified match was committed; entity-quality confirmation would tell you whether the substitution captured what the user meant.

    If none of the triggers fire, return stats-only and note "stats-only" in the self-check. Skip the pull even when TAM <= 50,000. The 50,000 ceiling is a maximum, not a trigger.

    When pulling: ~25 unsorted rows for ICP sanity (do top names look right, or include conglomerate / BPO / staffing noise?), directional geography and sub-industry shape, noise-rate estimation. The sample is unsorted: directional, not ranked. Do not compute employee or revenue percentages from it.

  2. Noise-adjusted TAM (mandatory when sample noise is at least 20 percent). Compute adjusted = round(operative_TAM x (1 - noise_rate), 2 sig figs). Re-classify the band against the adjusted number. Cite specific noisy rows. 20-60 percent noise signals revisiting the filter set, not shipping the count.

  3. SAM hypothesis (only if both inputs supplied). SAM count = operative TAM x addressable fraction. SAM revenue = SAM count x ARPA. Label clearly: hypothesis, not forecast.

  4. Self-check: headline rounded to at most 2 sig figs; step 3 branch dispositions (clean / brittle-surfaced / no-match) recorded for every free-text field; taxonomy mutex respected (only one of {LinkedIn, NAICS} queried unless user approved dual after a brittle hit); sparsity probe and noise adjustment run when applicable; sample pull triggered for a documented reason from step 8 OR correctly skipped as "stats-only"; unspecified dimensions flagged; persona criteria marked "not applied to company TAM"; region disambiguation resolved; refinement options name a specific dimension and an estimated post-refinement count.

  5. Present refinement options and loop. Too broad: 2-3 narrowing options with estimated impact. Too narrow: 2-3 widening options. Healthy band: tier segmentation or finalize. Always offer a "save filters" exit so downstream skills can consume the artifact. Re-run from step 3 when filters change and surface the diff. Terminate on finalize.

Show full SKILL.md (367 more words)Show less

Output Format

  • TL;DR: use case restated; headline ~[count] companies; band label. If the sparsity probe fired, show raw filtered, unfiltered, and operative TAM. If noise-adjusted, show raw, noise rate, adjusted, and the band classified against the adjusted number. 1-2 sentences on operational viability, dominant skew, most consequential refinement. If step 3 surfaced a brittle match, restate the chosen disposition (e.g. "fintech approximated by Financial Services parent, user-confirmed").
  • Filters Applied: dimension, value, source (user-specified, unspecified, approximation), and step-3 branch tag for any free-text field (clean / brittle-approximated / proxy). Persona criteria flagged "NOT applied to company TAM."
  • Sample Accounts (only when one of the step-8 triggers fired): up to 25 unsorted rows, with a one-line note citing WHICH trigger justified the pull. Sanity check; name the narrowing filter that removes any noise.
  • Sizing Band & Refinement: band label, 1-2 sentences on operational implication, 2-3 refinement options each naming a dimension change and an estimated post-refinement count. Or finalize.
  • SAM Hypothesis (only if both inputs supplied): TAM count, addressable fraction, SAM count, ARPA, SAM revenue. Hypothesis, not forecast.
  • Final Filter Set (on finalize): structured artifact with resolved values for every applied dimension plus operative TAM, band, pass count, and use case.

Limitations

  • Size and revenue are bucket filters; exact cutoffs cannot be expressed. Revenue buckets appear to be a deterministic employee-to-revenue heuristic, not real revenue data. 90%+ concentration in one bucket is expected; do not slice revenue after locking size.
  • No native sort on entity fetch; samples are directional, not ranked.
  • No metro taxonomy; geography resolves to country, region, or city autocomplete.
  • No similar-companies tool inside this skill; seed-account workflows belong elsewhere.
  • No sub-department job-function filter; persona is recorded only, never applied to the company count.
  • No Inc / Fortune ranking filters; public-vs-private is the only company-type boolean.
  • Industry taxonomy (LinkedIn vs NAICS) and country code vs region-country code are each mutually exclusive on a single query. Dual-querying is allowed under the brittle-branch exception in step 3, but the FINAL filter set must commit to one taxonomy per dimension.
  • Flagship vendor names (Snowflake, Databricks, Stripe) sometimes require a suffix-qualified phrasing to autocomplete cleanly; bare-token queries can return noise. Step 3's branch (b) handling exists specifically to surface this brittleness rather than silently substitute.

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

Files

Just SKILL.md in skills/market-sizing of explorium-ai/gtm-skills.

Open the folder on GitHubat commit f0efa6b

Compare with similar skills

Market Sizing next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Market Sizing compared with similar skills
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Market Sizing this skillexplorium-ai/gtm-skills175—~2.4kAutomated safety check: PassMIT
Competitor MapperMaxKmet/idea-validation-agents477—~3.3kAutomated safety check: PassMIT
TAM SAM SOM Calculatordeanpeters/Product-Manager-Skills7.2k1 repos~4.8kAutomated safety check: PassCustom licence
Market Sizing Analysisnicepkg/auto-company19411 repos~3.1kAutomated safety check: PassNone
Management ConsultantDogInfantry/claude-skill-management-consultant-B1132—~14kAutomated safety check: PassCustom licence
Market Sizing Frameworksslgoodrich/agents139—~3.3kAutomated safety check: PassCustom licence

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Works with

Questions about Market Sizing

What does Market Sizing do?

Market sizing skill for Claude Code and Codex: calculate TAM/SAM for any ICP against Explorium's 150M+ company dataset using real-time firmographic and technographic filters. Market Sizing is an agent skill from explorium-ai/gtm-skills. Market sizing skill for Claude Code and Codex: calculate TAM/SAM for any ICP against Explorium's 150M+ company dataset using real-time firmographic and technographic filters.

When should I use Market Sizing?

Market Sizing fits situations like: territory design; capacity planning; investor-ready market sizing; size the market.

How do I install Market Sizing in Claude Code?

Run `npx skills add explorium-ai/gtm-skills --skill market-sizing -a claude-code`. Or copy the skill folder (skills/market-sizing in explorium-ai/gtm-skills) into .claude/skills/market-sizing in your project. Claude Code loads it when a task matches its description.

How do I install Market Sizing in Codex?

Run `npx skills add explorium-ai/gtm-skills --skill market-sizing -a codex`. Or copy the skill folder (skills/market-sizing in explorium-ai/gtm-skills) into .agents/skills/market-sizing in your project. Codex loads it when a task matches its description.

Can I use Market Sizing in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add explorium-ai/gtm-skills --skill market-sizing -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/market-sizing, .gemini/skills/market-sizing, .github/skills/market-sizing and .opencode/skills/market-sizing in your project.

What does Market Sizing need to run?

SKILL.md names no scripts, command-line tools or credentials: Market Sizing is instructions for the agent only.

Does Market Sizing access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Market Sizing safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Market Sizing use?

Market Sizing is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Market Sizing use?

About 2.4k tokens (SKILL.md is roughly 9.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Market Sizing?

Skills that share tags, products or a category with Market Sizing: Competitor Mapper (MaxKmet/idea-validation-agents, 477 stars), TAM SAM SOM Calculator (deanpeters/Product-Manager-Skills, 7.2k stars), Market Sizing Analysis (nicepkg/auto-company, 194 stars) and Management Consultant (DogInfantry/claude-skill-management-consultant-B1, 132 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Market Sizing?

explorium-ai (a GitHub organization) maintains it in explorium-ai/gtm-skills, which has 175 GitHub stars. The repository holds 17 skills in this directory. The repository was last updated on October 8, 2026.

Source: explorium-ai/gtm-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.