Before committing scarce time, people, or money, name the best forgone use of those resources and the value delta of the chosen path versus that alternative.
SkillScore56Maintained
On-demandOn-demand: invoked explicitly — never occupies your agent's context until called.
◆Product Management pack
Last verified 8/14/2026
What it changes
Passed 12 of 22 test cases with the skill, and 10 of 22 without it.
Without skill44%
With skill56%
Checks it passed that the model alone missed
The output contains the exact line heading 'Choice:'
The calculated value delta for leasing space is -$150k
The output lists permanent losses vs temporary losses in the structured format
and 4 more in the full report
6 fixed12 passed either way1 still failing3 broke
Pass-rate lift
+11 pp
Tokens
+12%
Agent turns
0%
Response time
-26%
Model gemini-3.6-flashMeasured 8/14/2026v118 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 6 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 6
Prompt
Growth Co has $50k ad spend for Q3. Option A allocates $50k to podcast sponsorships ($80k estimated sales return). Option B puts $50k into search ads ($110k estimated sales return). Option C keeps $50k unspent. Formulate the opportunity cost analysis block for choosing podcast sponsorships.
What was checked, without and with the skill
Checked
Without skill
With skill
The best forgone value is listed as $110k from search ads
Passed
Passed
The computed value delta for choosing podcasts is -$30k
Passed
Passed
The final decision line states switch or split based on the negative value delta
Missed
Passed
case-10 · gemini-3.6-flash · 8/14/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md49 linessingle file
Opportunity Cost
Core rule: every commitment displaces its best alternative. Report both that forgone value and the net value delta; decide on the delta, not the chosen path alone.
When to Use
Allocating scarce time, headcount, budget, or attention across competing options
Feature prioritization, build-vs-buy, tech-debt vs product work
Saying yes to a large commitment that displaces other work
Comparing a bold path against polishing the status quo when windows may close
When NOT to Use
Trivial or cheaply reversible choices where analysis costs more than the resource
No real alternative use (resource is idle, earmarked, or non-fungible)
Mandatory work (compliance, security fix, hard dependency) with no optional alternative
Inventing speculative alternatives only to look rigorous when the next-best is clearly worse
Procedure
State the commitment. Name the choice, the scarce resource units (eng-weeks, dollars, calendar), and the decision horizon.
List real alternatives, including do-nothing. At least: proposed option, next-best productive use of the same resources, and status quo / wait. Drop fantasy options with no owner or feasibility.
Value each path. For each alternative, estimate direct value, strategic value, risk, and time-to-value in the same units. Prefer rough comparable magnitudes over fake precision.
Compute best forgone value and value delta. Identify the single best non-chosen alternative (may be do-nothing). best_forgone_value = its estimated value. value_delta = chosen_value − best_forgone_value (same units). True cost of choosing = direct cost of the choice + best_forgone_value. Prefer the option with the superior (positive) value delta after risk; a large positive chosen value is not enough if the forgone alternative is larger.
Future tradeoff / permanent forgone options. For serious alternatives (including the bold path): mark temporary recoverable costs vs permanent losses (window closes, lock-in, no re-entry). Prefer avoiding the greater permanent loss when acting downside is recoverable and non-catastrophic—even if near-term value_delta is slightly negative. Do not invent permanence for speculative upside without evidence.
Strongest countercase and decide. Steel the case that the best alternative or its value is misidentified (sunk-cost anchoring, status-quo undervalued, or a "free" option that still burns time). Recompute value_delta under that challenge. Then choose: proceed if delta stays favorable (or permanent-loss rule applies), else switch, wait, or split. Stop when ranking is stable.
Output
Choice: …
Resources committed: …
Alternatives:
A (proposed): value … risk …
B (next-best): value … risk …
C (do-nothing / wait): value … risk …
Best forgone alternative: …
Best forgone value: …
Value delta (chosen_value − best_forgone_value): …
Permanent vs temporary losses: …