A purchasing agent comparing two suppliers works from structured data: price, specifications, delivery windows, ratings, stock levels. In controlled benchmarks, these signals plus position on the page and platform endorsements account for nearly all of an agent's selection behavior. Call this legible value: competitive advantage that fits into fields an agent can read and rank.
Then there's everything that doesn't fit. Whether a vendor absorbs logistics errors without friction. Whether a design firm's aesthetic suits your organization's culture. Whether a supplier's judgment holds up when the situation gets ambiguous. People who work with a vendor know these things intimately, but the knowledge lives in experience and accumulated context, not in any product feed.
The distinction matters because agents affect each side differently. Legible advantages get competed away faster, because agents comparison-shop with mechanical efficiency. Illegible advantages don't get surfaced at all. An agent can't evaluate what it can't encode, which means the qualities that often determine whether a relationship actually works are precisely the ones that agent-mediated commerce routes around.
Agents evaluate well: price, specs, ratings, availability, delivery speed, review volume, structured certifications, platform endorsement tags
Agents can't evaluate: relationship history with a specific account, contextual judgment under ambiguity, aesthetic fit, cultural alignment, willingness to make exceptions when circumstances warrant them
Legibility shifts over time. Return rates made durability evaluable. NPS scores made satisfaction evaluable. Today's illegible attribute can become tomorrow's structured field, but encoding always strips context.
Benchmark finding: In the ACES framework, position effects on agent choices were roughly 8-10x larger than quality-price variation. Agents respond to structured signals, but the signals they weight most heavily don't necessarily reflect buyer interest.
Where the boundary bites hardest: products whose real advantage is partially legible, but the part that isn't is the part the buyer would care about most.