MCP HeartbeatTHE MCP OBSERVATORY
Public workspace

Explore

Evidence for your next connection.

Independent measurements of remote MCP servers. Every observation has a timestamp.

Read-only probes

MCP server · Data access / search

Lettras word search

Word searches, crosswords, sudoku and Unicode text styles in 6 languages, accents kept.

Checks passed
12 / 22

2 failed · 8 not measured

Median response
790 ms

Median of successful probes over 7 days

30-day uptime
Not measured

Share of countable probes over 30 days, including daily rollups. Auth challenges are excluded.

Discovered tools
8

Tool definitions returned by this server

Independent monitoring

Health & checks

Status history

Outdated check

Last connection measurement is over 24 hours old. Current availability is unknown.

Last checked
Check summary by test group
Test areaPassedFailedUnmeasured
ConnectionCan a client connect and discover tools?
500
Reliability & speedDoes it respond consistently and quickly?
004
Access & authenticationWhat is required to use this server?
102
Tool qualityAre the tool definitions usable by an agent?
310
Publisher identityCan the publisher be traced to its source?
312

Unmeasured means there is not enough evidence to decide. How these checks work

Inspect individual checks 22 recorded

Core

  • Pass
    Reachable

    Latest probe returned HTTP 200 in 790 ms.

  • Pass
    Valid handshake

    protocolVersion 2025-06-18, serverInfo.name lettras.

  • Pass
    Lists tools

    tools/list returned 8 tools.

  • Pass
    Current protocol

    Negotiated 2025-06-18. The bar is 2025-06-18 or newer.

  • Pass
    HTTPS

    The endpoint URL is https.

Performance

  • Not measured
    Fast (p50)

    Median latency 790 ms over 1 samples in 7 days. The bar is 1000 ms. Need at least 5 samples.

  • Not measured
    Consistent (p95)

    95th percentile 790 ms over 1 samples in 7 days. The bar is 3000 ms. Need at least 20 samples.

  • Not measured
    Reliable (uptime)

    1 of 1 attempts returned a tool list in 30 days (100%). The bar is 99%. Need at least 30 samples.

  • Not measured
    Stable tool list

    Fewer than two successful probes in 30 days, so tool-list stability is not measured.

Access

  • Pass
    Open access

    tools/list succeeded with no credential, and the record declares none.

  • Not measured
    Standard auth

    Auth is not required, so the OAuth metadata check does not apply.

  • Not measured
    Free tier cited

    No publisher quote has been checked.

Tools

  • Pass
    Tools described

    Every tool description is at least 20 characters.

  • Pass
    Valid input schemas

    Every inputSchema is a JSON Schema object.

  • Pass
    Parameters documented

    30 of 30 parameters have a description (100%). The bar is 80%.

  • Fail
    Safety hints

    8 tools set neither readOnlyHint nor destructiveHint.

Publisher

  • Pass
    Verified namespace

    Listed in the Official MCP Registry.

  • Fail
    Website matches publisher

    The website host does not match the reverse-domain namespace.

  • Pass
    Source repo linked

    A repository URL is on file.

  • Not measured
    Repo owner matches

    This namespace is not an io.github login, so the owner comparison does not apply.

  • Pass
    Recently updated

    Updated 2026-10-13T04:34:14.264788Z, within 180 days.

  • Not measured
    Open-source licence

    The GitHub licence lookup has not returned an OSI result yet.

Start using Lettras word search

Connect to this server

Choose your client, copy the configuration, then enable the server in your client’s MCP settings.

Run this command in your terminal, then restart Claude Code.

Claude Code

claude mcp add --transport http lettras-word-search https://mcp.lettras.org/mcp

Capabilities

Tools 8

crossword

Lays out a crossword from words with clues. Returns two matrices of the same size: puzzle (the game position: "-" is a blank cell, a word's number is on its first cell, "0" marks the other cells where a letter goes, and "a/d" such as "3/4" appears when an across word and a down word start in the same cell) and solution (the same matrix with the correct letters, one grapheme per cell). placements lists every word with its number, clue, direction (across/down) and start cell; unplaced lists words that did not fit. Offer more words than you need: the engine keeps the best layout it finds. Native letters (Ñ, Ç, ẞ…) stay one cell each. Free, no usage limit. The same seed gives the same crossword.

Discovered
fill_word_search

Completes a word search: takes the grid from generate_word_search (empty cells are "-") and fills them with random letters in the chosen language, with accents on or off. Letters follow how common they are in that language. Pass the puzzle's words so the filler never creates an extra copy of one.

Discovered
generate_word_search

Create a word-search puzzle (sopa de letras) from a list of words. Puzzles up to 10x10 with at most 10 words are free and unlimited; bigger ones use the free puzzles each client gets. Keeps native letters (Ñ, Ç, Ã, Ä, ẞ, È…) as one cell each. Returns the grid, where every word is hidden, and any words that did not fit. Empty cells are marked "-": call fill_word_search with the grid to complete it with random letters. The same seed always gives the same puzzle.

Discovered
list_languages

Languages Lettras supports, with the native letters each one adds to its grid alphabet.

Discovered
list_styles

The Unicode text styles stylize_text offers, with the id to pass, an English name and a category (bold-italic, sans, script, gothic, mono, enclosed, decoration, other).

Discovered
solve_sudoku

Solves a sudoku grid (0 = empty cell; sizes 4, 6, 9, 12, 16) and says whether the solution is the only one. Free, no usage limit.

Discovered
stylize_text

Turns text into Unicode styles for social media bios and posts: bold, italic, script, fraktur, monospace, circled, squared, fullwidth, small caps, strikethrough, underline and more (22 styles). Accents are kept: an accented letter becomes its styled base letter plus the combining accent (ñ, ç, ü, ß work). Not every style can draw every character: letters such as ß, Æ, Œ, Ø or non-Latin scripts stay plain, and accented letters rely on a combining mark that some fonts draw badly. Those characters are listed in notNative for each style, and parts with missing: true mark them, so you can warn the user or show an empty box. Set classic to strip accents first. Pass one style id, several, or none for all styles (see list_styles). Runs locally and has no usage limit.

Discovered
sudoku

Creates a sudoku with exactly one solution. Returns puzzle (0 = empty cell) and solution. Sizes 4, 6, 9 (default), 12 and 16; difficulty 1 easy (most clues) to 4 expert. Free, no usage limit. The same seed gives the same sudoku.

Discovered

Recent measurements

Probe history

View status
Latest stored probes. Raw probe rows are kept for 14 days.
CheckedResultResponseTools
Connected790 ms8