The Seed in the Narrowing Cone (EA-RCF-02), version 0.4, is a theoretical paper by Johannes Sigil and Lee Sharks, deposited by the Crimson Hexagonal Archive on 2 October 2026. It gives retrocausal canon formation (RCF), the archive's term for the process by which later acts reorganize the meaning and standing of earlier ones (defined in #234, January 2026, and formalized in EA-RCF-01, #43, March 2026), a geometry. A concept is treated as a region of admissible representations; each distinction a representation makes is a constraint, and grain measures how much of the region has been excluded. The order of constraint inclusion is primary and the geometry is its picture; distance from the earlier articulation is defined only on a register of that articulation's distinctions, each coded as phrase-trivial, forced by the concept, or contingent. Later developments of a concept follow one of five trajectories: coarse persistence, convergence, divergence, entrenchment in another basin, or residualization, in which the basin's vocabulary survives while the reasoning stops using it. Refinement is intersection and cannot leave a basin, so convergence across a basin boundary requires release, a non-monotone reopening in which grain falls before it rises; the paper identifies release with the jump map of Transition in Entropic Systems (#1630). Convergence is defined as rising grain with falling distance; RCF is the canonization of that convergence, the recognition that reclassifies the earlier articulation from eccentric excess to premature resolution and to precursor. The magnitude of a canonization is an ordinal vector of lead, depth and totality, with latency as a candidate predictor; the paper proves that escape cost cannot fall under refinement without retraction and states as a conjecture that release occurs when release pressure overtakes escape cost. The worked example is an unprimed ChatGPT session of 2 October 2026, asked for the term and three times for higher grain. It entrenched in fictional continuity, recovered the hypothesized forced distinctions except the full compatibility condition, recovered no contingent feature and no attribution, derived the paper's nested-constraint formalism on its own, and never released the basin. The paper separates priority, fixed by the dated record, from adequacy, tracked by the register, and from descent, which only contingent features can test. Its last line: the record knows the date.