diff --git a/src/lib/dict.ts b/src/lib/dict.ts
index 50603a6..cb679c9 100644
--- a/src/lib/dict.ts
+++ b/src/lib/dict.ts
@@ -25,6 +25,13 @@ export class Dict {
 		return Dict.from_lines(content.split("\n"), length);
 	}
 
+	constraint(at: number, letter: string) {
+		const to_delete = new Set<string>();
+		for (const word of this.words.values()) if (word[at] !== letter) to_delete.add(word);
+		for (const item of to_delete) this.words.delete(item);
+		return to_delete.size;
+	}
+
 	[Symbol.for("Deno.customInspect")]() {
 		return `Dict { ${this.words.size} words, ${this.letters.size} letters }`;
 	}
diff --git a/src/lib/game/proxy.ts b/src/lib/game/proxy.ts
index 1e55085..ced5f21 100644
--- a/src/lib/game/proxy.ts
+++ b/src/lib/game/proxy.ts
@@ -12,7 +12,9 @@ export class ManualProxy implements Gaming {
 
 	guess(guess: string, _known: string): Awaitable<GuessResult> {
 		console.log("<proxy> Guessing:", guess);
-		return read_until_correct(this.word_length);
+		const result = read_until_correct(this.word_length);
+		console.log();
+		return result;
 	}
 
 	length(): number {
@@ -25,7 +27,10 @@ function read_until_correct(length: number): GuessResult {
 		const input = prompt("<proxy>   Result:");
 		assertExists(input);
 		const informations = parse_input(input, length);
-		if (informations === null) continue;
+		if (informations === null) {
+			console.log("<proxy> incorrect input, try again");
+			continue;
+		}
 		if (informations.every((i) => i.kind === "there")) return { kind: "success" };
 		return { kind: "failure", informations };
 	}
@@ -34,9 +39,9 @@ function read_until_correct(length: number): GuessResult {
 function parse_input(input: string, length: number) {
 	const parsed = [] as Info[];
 	for (const character of input.trim()) {
-		if (character === "n") parsed.push({ kind: "abscent" });
-		if (character === "i") parsed.push({ kind: "somewhere" });
-		if (character === "y") parsed.push({ kind: "there" });
+		if (character === ".") parsed.push({ kind: "abscent" });
+		if (character === "-") parsed.push({ kind: "somewhere" });
+		if (character === "+") parsed.push({ kind: "there" });
 	}
 	if (parsed.length !== length) return null;
 	else return parsed;
diff --git a/src/lib/guesser.ts b/src/lib/guesser.ts
index c0afca6..841dc88 100644
--- a/src/lib/guesser.ts
+++ b/src/lib/guesser.ts
@@ -53,13 +53,13 @@ export class Guesser implements Guessing {
 		return null;
 	}
 
-	learn_does_not_exist(letter: string) {
+	public learn_does_not_exist(letter: string) {
 		const letter_info = this.informations.get(letter);
 		assertExists(letter_info);
 		letter_info.exists = false;
 	}
 
-	learn_does_exist(letter: string) {
+	public learn_does_exist(letter: string) {
 		const letter_info = this.informations.get(letter);
 		assertExists(letter_info);
 		letter_info.exists = true;
@@ -68,7 +68,8 @@ export class Guesser implements Guessing {
 		for (const info of this.informations.values()) if (info.exists === "unknown") info.exists = false;
 	}
 
-	learn_letter_at(letter: string, at: number) {
+	public learn_letter_at(letter: string, at: number) {
+		this.learn_does_exist(letter);
 		const letter_info = this.informations.get(letter);
 		assertExists(letter_info);
 		letter_info.at.add(at);
@@ -78,7 +79,7 @@ export class Guesser implements Guessing {
 		}
 	}
 
-	learn_letter_not_at(letter: string, at: number) {
+	public learn_letter_not_at(letter: string, at: number) {
 		const letter_info = this.informations.get(letter);
 		assertExists(letter_info);
 		letter_info.not_at.add(at);
diff --git a/src/lib/prompt.ts b/src/lib/prompt.ts
new file mode 100644
index 0000000..01f42a8
--- /dev/null
+++ b/src/lib/prompt.ts
@@ -0,0 +1,46 @@
+import { assertExists } from "https://deno.land/std@0.224.0/assert/assert_exists.ts";
+
+import { enumerate } from "./utils.ts";
+
+export function initialize_prompt() {
+	console.log("Please input initial state of the game. Format is :");
+	console.log("  letter    [a-z]    known letter");
+	console.log("  dot       .        unknown letter");
+	console.log("example : .rb..");
+	console.log("");
+	const inputted = parse_initialization_until_correct();
+	console.log("");
+	console.log("From now on, please try the following guesses and report results. Format is :");
+	console.log("  plus     +    correct");
+	console.log("  minus    -    wrong placement");
+	console.log("  dot      .    incorrect");
+	console.log("example : -++..");
+	console.log();
+	return inputted;
+}
+
+function parse_initialization_until_correct() {
+	let input = prompt("initial :");
+	while (true) {
+		assertExists(input);
+		const parsed = parse_initialization(input);
+		if (parsed === null) input = prompt("Invalid, please try again :");
+		else return parsed;
+	}
+}
+
+function parse_initialization(input: string) {
+	const code_a = "a".charCodeAt(0);
+	const code_z = "z".charCodeAt(0);
+	let length = 0;
+	const constraints = [] as [number, string][];
+	for (const [index, char] of enumerate(input.trim().toLowerCase())) {
+		length += 1;
+		if (char === ".") continue;
+		const code = char.charCodeAt(0);
+		if (code < code_a) return null;
+		if (code > code_z) return null;
+		constraints.push([index, char]);
+	}
+	return { length, constraints };
+}
diff --git a/src/manual_proxy.ts b/src/manual_proxy.ts
old mode 100644
new mode 100755
index c0a80b7..4ffaf87
--- a/src/manual_proxy.ts
+++ b/src/manual_proxy.ts
@@ -3,6 +3,7 @@
 import { Command } from "https://deno.land/x/cliffy@v1.0.0-rc.4/command/mod.ts";
 
 import { Dict, Guesser, ManualProxy, Runner } from "./lib/lib.ts";
+import { initialize_prompt } from "./lib/prompt.ts";
 import { VerboseLogging } from "./lib/runner.ts";
 
 import { francais } from "../data/data.ts";
@@ -15,23 +16,18 @@ async function main() {
 		.option(
 			"-f, --file <path:string>",
 			"Sets dictionnary to use words from (defaults to internal french dict).",
-		).option(
-			"-n, --length <length:number>",
-			"Length of the word to use from the dictionnary.",
-			{ default: 6 },
-		).option(
-			"-w, --wait <wait:number>",
-			"Time to wait between guesses, in ms.",
-			{ default: 0 },
 		).parse(Deno.args);
 
-	let dict = Dict.from_lines(francais, args.options.length);
-	if (args.options.file !== undefined) dict = await Dict.from_text_file(args.options.file, args.options.length);
+	const init = initialize_prompt();
+
+	let dict = Dict.from_lines(francais, init.length);
+	if (args.options.file !== undefined) dict = await Dict.from_text_file(args.options.file, init.length);
+	for (const [index, letter] of init.constraints) dict.constraint(index, letter);
 
 	const guesser = new Guesser(dict);
-	const game = new ManualProxy(args.options.length);
+	const game = new ManualProxy(init.length);
 
-	const runner = new Runner(game, guesser, new VerboseLogging(), args.options.wait);
+	const runner = new Runner(game, guesser, new VerboseLogging());
 	await runner.play_all();
 }