hn-tech-signal-mcp
This server aggregates tech and AI intelligence from HackerNews, arXiv, Lobste.rs, and GitHub into structured briefings — no API key required — enabling AI assistants to monitor the research and developer landscape.
Browse HackerNews feeds: Fetch stories from six feeds (top, best, new, Ask HN, Show HN, job posts) with score filtering.
Search HackerNews history: Full-text search across all historical HN content via Algolia, with date range (up to 365 days) and tag filters.
Read HackerNews comment threads: Retrieve nested comment threads with configurable depth (1–4 levels) and comment budget (1–100 comments).
Fetch latest arXiv papers: Get the newest AI/ML research submissions by category (cs.AI, cs.LG, cs.CL, cs.CV, cs.NE, stat.ML).
Search arXiv papers: Search by keyword, title, abstract, or author, with optional category filtering.
Browse Lobste.rs hot stories: Fetch curated tech stories, filterable by tag (e.g. 'ai', 'ml', 'security').
Discover trending GitHub repos: Search repos by topic (e.g. 'llm', 'mcp', 'ai-agents'), sortable by stars or recent activity, with a minimum star count filter.
Generate a unified tech signal digest: One call aggregates signals from all four sources into a structured briefing, optionally focused on a specific topic like 'MCP' or 'agents'.
Provides full-text search across all HackerNews history via the Algolia API.
Fetches latest arXiv papers by category and supports keyword/title/author search.
Retrieves HackerNews top, best, and new stories using the Firebase API.
Searches trending AI repositories and other repos on GitHub by topic, stars, and activity.
Gets hottest Lobste.rs stories, with optional tag filtering.
Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@hn-tech-signal-mcpGive me a tech signal digest on AI today"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
🇨🇭 Part of the Swiss Public Data MCP Portfolio
📡 hn-tech-signal-mcp
MCP server for global tech & AI signal intelligence — aggregates HackerNews, arXiv, Lobste.rs and GitHub into a structured briefing. No API key required.
Demo
Overview
hn-tech-signal-mcp turns any AI assistant into a proactive tech intelligence analyst. The server aggregates four signal layers — research frontier, developer discourse, curated signal, and open-source practice — into a single, structured briefing.
No authentication required. All four data sources are public APIs. Optional: set GITHUB_TOKEN for higher GitHub rate limits (5,000 req/h vs. 60 req/h unauthenticated).
Anchor demo query: "Give me a tech signal digest on AI today — what is happening in research, developer discourse and open source?"
Related MCP server: harness-feed-mcp
Signal Architecture
FRONTIER arXiv API → Latest AI/ML papers (cs.AI, cs.LG, cs.CL, cs.CV)
DISCOURSE HackerNews → Six feeds + Algolia search + comment threads
Lobste.rs → Curated, lower-noise tech signal
PRACTICE GitHub Search → What engineers are actually building right now
HN Show HN → What individuals are shipping this weekThink of the four layers as a radar: arXiv shows what's coming over the horizon, HN and Lobste.rs show what practitioners are discussing, and GitHub shows what teams are actually shipping.
Within the discourse layer there are two levels of depth. The feeds and the search tell you what is being discussed; hn_discussion tells you what is actually being argued — the counter-arguments and the "we tried this in production" replies that carry the real signal.
Features
🔬 Research frontier – Latest arXiv papers by category (cs.AI, cs.LG, cs.CL, and more)
🔍 arXiv full-text search – Find papers by keyword, title, or author
🗣️ HackerNews feeds – top, best, new, Ask HN, Show HN and YC job posts
🔎 HackerNews search – Full history via Algolia, with date range filter
💬 HackerNews comment threads – Read the actual discussion under a story, nested, with a bounded fetch budget
🔧 Lobste.rs hottest – Curated developer signal, filterable by tag
🛠️ GitHub trending AI repos – Search by topic, stars, sort by activity or popularity
📋 Tech signal digest – One-call cross-source briefing in Markdown
☁️ Dual transport – stdio for Claude Desktop, Streamable HTTP for cloud deployment
# | Tool | Source | Description |
1 |
| HackerNews | Six feeds: top/best/new/ask/show/job, with score filter |
2 |
| HN Algolia | Full-text search across all HN history |
3 |
| HackerNews | Nested comment thread under a story |
4 |
| arXiv | Latest papers by category (cs.AI etc.) |
5 |
| arXiv | Search papers by keyword/title/author |
6 |
| Lobste.rs | Curated tech stories, filterable by tag |
7 |
| GitHub | Trending AI repos by topic and stars |
8 |
| All sources | Aggregated Markdown briefing |
HackerNews feeds
Feed | Content | Upstream size |
| Front page as ranked right now | 500 items |
| Highest-voted recent stories | 200 items |
| Newest submissions, unfiltered | 500 items |
| Ask HN — what practitioners are stuck on | ~30 items |
| Show HN — what people are shipping | 200 items |
| YC portfolio job posts ( | ~30 items |
ask and job are short feeds upstream, so a large limit may return fewer stories than requested.
Prerequisites
Python 3.11+
uvorpipNo API key required
Optional:
GITHUB_TOKENfor higher GitHub rate limits
Installation
# Recommended: uvx (no install step needed)
uvx hn-tech-signal-mcp
# Alternative: pip
pip install hn-tech-signal-mcpQuickstart
# Start the server (stdio mode for Claude Desktop)
uvx hn-tech-signal-mcp
# With optional GitHub token for higher rate limits
GITHUB_TOKEN=ghp_yourtoken uvx hn-tech-signal-mcpTry immediately in Claude Desktop:
"Give me a tech signal digest on AI today" "What are the latest cs.AI papers from the last 48 hours?" "What is HackerNews discussing about MCP this week?" "Show me trending GitHub repos for the topic 'ai-agents'"
Configuration
Environment Variables
Variable | Default | Description |
| – | Optional. GitHub personal access token. Without it: 60 req/h. With it: 5,000 req/h. The token is only sent to |
|
| Transport: |
|
| Bind host for HTTP transport. Non-loopback values require |
|
| Port for HTTP transport |
| – | Required when |
Claude Desktop Configuration
{
"mcpServers": {
"hn-tech-signal": {
"command": "uvx",
"args": ["hn-tech-signal-mcp"],
"env": {
"GITHUB_TOKEN": "ghp_yourtoken_optional"
}
}
}
}Config file locations:
macOS:
~/Library/Application Support/Claude/claude_desktop_config.jsonWindows:
%APPDATA%\Claude\claude_desktop_config.json
After restarting Claude Desktop, all 7 tools are available.
Cloud Deployment (Streamable HTTP)
For use via claude.ai in the browser (e.g. on managed workstations):
Render.com (recommended):
Push/fork the repository to GitHub
On render.com: New Web Service → connect GitHub repo
Optionally set
GITHUB_TOKENin the Render dashboardIn claude.ai under Settings → MCP Servers, add:
https://your-app.onrender.com/mcp
# Local HTTP mode (binds 127.0.0.1 by default)
MCP_TRANSPORT=streamable_http MCP_PORT=8000 python -m hn_tech_signal_mcp.server
# Public bind (requires bearer token, intended behind a reverse proxy that terminates TLS)
MCP_TRANSPORT=streamable_http \
MCP_HOST=0.0.0.0 \
MCP_BEARER_TOKEN="$(openssl rand -hex 32)" \
python -m hn_tech_signal_mcp.serverHardening: the server refuses to bind to non-loopback hosts unless
MCP_BEARER_TOKENis set. Run cloud deployments behind a TLS-terminating reverse proxy (Render, Fly, Caddy, …) and treatMCP_BEARER_TOKENas the shared client secret your proxy enforces.
Architecture
┌─────────────────┐ ┌─────────────────────────────────┐ ┌───────────────────────┐
│ Claude / AI │────▶│ HN Tech Signal MCP │────▶│ HackerNews Firebase │
│ (MCP Host) │◀────│ (MCP Server) │────▶│ HN Algolia Search │
└─────────────────┘ │ │────▶│ arXiv.org (Atom API) │
│ 8 Tools │────▶│ Lobste.rs JSON API │
│ Stdio | Streamable HTTP │────▶│ GitHub Search API │
└─────────────────────────────────┘ └───────────────────────┘Architecture decision
This server uses Architecture A (live API only, two paths per source). There is no bulk dump to fall back on.
Rationale (verified live on 2026-07-28 against the official HackerNews API):
All six feed endpoints (
{top,best,new,ask,show,job}stories.json) answer HTTP 200 with 29–500 IDs. No auth, no rate-limit headers,Cache-Control: no-cache.HackerNews publishes no bulk export, so caching is entirely this server's responsibility. TTLs live in
CACHE_TTL.The Firebase API has no search. Historical and full-text queries go through the Algolia index instead — that is the second path, used by
hn_search.item/<id>.jsonis one request per item. Feeds and comment threads therefore fan out, which is why both are bounded (HN_MAX_CONCURRENCY,max_comments).
Consequences:
Every upstream call retries with exponential backoff (2s / 4s / 8s) on network errors, 5xx and 429. Other 4xx fail fast.
One process-wide pooled
httpx.AsyncClient, closed via the FastMCP lifespan.Unknown item IDs return HTTP 200 with a
nullbody rather than a 404 —hn_discussiontranslates that into an explicit "no item found" message.
Project Structure
hn-tech-signal-mcp/
├── src/
│ └── hn_tech_signal_mcp/
│ ├── __init__.py
│ └── server.py # All 8 tools
├── tests/
│ ├── __init__.py
│ └── test_server.py # 64 unit + 12 live tests
├── pyproject.toml
├── CHANGELOG.md
├── CONTRIBUTING.md
├── LICENSE
├── README.md # This file (English)
└── README.de.md # German versionMCP Protocol Version
This server speaks two protocol eras over the same endpoint. The client's first request on a connection decides which one applies; a later claim from the other era is refused.
Era | Revision | Who reaches it |
|
| What today's clients speak. The server answers with the revision asked for, or with the |
Per-request envelope |
| A request carrying the |
Both revisions are pinned in
tests/test_protocol_version.py and asserted
against the installed SDK, so a Dependabot bump of mcp cannot move either one
silently. This server builds no ASGI app to send an initialize through, so
the gate asserts the SDK constants rather than a measured response — the
weaker form, named rather than left unsaid.
Note that the SDK's LATEST_PROTOCOL_VERSION is an alias for the modern
era, not for the handshake era — pinning against it alone would leave the era
that current clients actually negotiate free to drift.
Update policy. When the gate fails, do not edit the constant blindly: read
the spec changelog between the two revisions, verify the server still behaves,
then move the constant, this section, README.de.md and
CHANGELOG.md together.
Testing
# Unit tests (no network required)
PYTHONPATH=src pytest tests/ -m "not live"
# Live integration tests (requires network)
PYTHONPATH=src pytest tests/ -m "live"Example Use Cases
KI-Fachgruppe / AI Working Group
"Give me a tech signal digest on AI today"
→ tech_signal_digest(focus="AI")
"What are the top 5 arXiv papers on LLM agents this week?"
→ arxiv_search(query="LLM agents", category_filter="cs.AI", limit=5)
"What is HackerNews discussing about model context protocol?"
→ hn_search(query="model context protocol", days_back=30)Research Monitoring
"Show me the latest NLP papers from arXiv"
→ arxiv_latest(category="cs.CL", limit=10)
"Search arXiv for papers on retrieval-augmented generation"
→ arxiv_search(query="retrieval augmented generation RAG", limit=10)Open Source Intelligence
"What AI agent frameworks are trending on GitHub?"
→ github_trending_ai(topic="ai-agents", sort="updated", limit=10)
"Show me the most starred MCP-related repos"
→ github_trending_ai(topic="mcp", sort="stars", min_stars=50)
[→ More use cases by audience →](EXAMPLES.md)arXiv Category Reference
Category | Full Name | Key Topics |
| Artificial Intelligence | Agents, planning, knowledge representation |
| Machine Learning | Training, optimisation, generalisation |
| Computation & Language | NLP, LLMs, translation, summarisation |
| Computer Vision | Image recognition, generation, multimodal |
| Robotics | Embodied AI, navigation |
| Statistics ML | Probabilistic methods, Bayesian ML |
Rate Limits
Source | Auth Required | Limit |
HackerNews Firebase | No | Very generous (Firebase) |
HN Algolia Search | No | ~10,000 req/hour |
arXiv | No | ~3 req/second (be respectful) |
Lobste.rs | No | Reasonable use |
GitHub Search | No | 60 req/hour |
GitHub Search |
| 5,000 req/hour |
Known Limitations
GitHub rate limit: 60 req/h without token. Set
GITHUB_TOKENfor production use.arXiv: Papers may take up to 24h to appear after submission. Weekends/holidays have delayed batches.
HackerNews: Top/best story lists update every few minutes. Very new stories may have low scores.
HackerNews
ask/jobfeeds: Only ~30 items exist upstream, so a largelimitreturns fewer stories than requested. Job posts carrytype: "job", no comment count, and a score of 1.hn_discussionis always a sample, never the full thread: one request per comment upstream means popular stories (900+ comments) cannot be fetched whole. The budget is split across nesting levels and spread round-robin across sibling threads, so you get a representative cross-section rather than one exhaustively-read sub-thread. Check thetruncatedflag.hn_discussioncomment text is plain text, not HTML: HN's markup is stripped for readability. Do not re-render the output as HTML — the conversion is not a sanitiser.Lobste.rs: Smaller community than HN; tech-focused but may not cover all AI topics.
tech_signal_digest: Makes ~4 concurrent requests; if one source is slow it may delay the full response.
Synergies with Other MCP Servers
hn-tech-signal-mcp combines well with:
Combination | Use Case |
| Global research + Swiss institutional media coverage |
| Tech discourse + Swiss regulatory context |
| AI research trends + education policy data |
| Tech landscape + Swiss economic/structural data |
Safety & Limits
Read-only: All tools perform HTTP GET requests only — no posts, comments, votes, or writes are issued upstream.
No personal data: The server queries public tech aggregators. No PII is collected; author handles in public posts/papers are returned as-is from upstream and never enriched or cross-referenced.
Rate limits: See the Rate Limits table. arXiv's ≤3 req/sec guidance is respected by default; GitHub search is capped at 60 req/h without a
GITHUB_TOKEN. A request timeout is enforced per call.No bulk harvesting: This server is built for interactive, conversational use — not for scraping or mirroring. Do not use it to bypass upstream pagination or ToS limits.
Terms of service: Data is subject to the ToS of each source — HackerNews, arXiv API, Lobste.rs, GitHub.
No guarantees: Community project, not affiliated with HackerNews / Y Combinator, arXiv / Cornell, Lobste.rs, or GitHub. Availability depends on upstream APIs.
Changelog
See CHANGELOG.md
Contributing
See CONTRIBUTING.md (Deutsch).
Security
See SECURITY.md (Deutsch) for the security posture and how to report a vulnerability.
License
MIT License — see LICENSE
Author
Hayal Oezkan · malkreide
Credits & Related Projects
HackerNews API: hacker-news.firebaseio.com — Y Combinator / Firebase
arXiv API: export.arxiv.org — Cornell University / arXiv.org
Lobste.rs API: lobste.rs — community-run
GitHub API: api.github.com — GitHub / Microsoft
Protocol: Model Context Protocol — Anthropic / Linux Foundation
Related: news-monitor-mcp — Swiss institutional media monitoring
Portfolio: Swiss Public Data MCP Portfolio
Installation
Run via uv's uvx — no clone or manual install needed. Add to your MCP client config (mcpServers for Claude Desktop, Cursor and Windsurf; use a top-level servers key for VS Code in .vscode/mcp.json):
{
"mcpServers": {
"hn-tech-signal-mcp": {
"command": "uvx",
"args": [
"hn-tech-signal-mcp"
]
}
}
}Available Tools
8 toolsarxiv_latestARead-onlyIdempotent
Fetch the most recently submitted papers from arXiv AI/ML categories.
Papers appear hours before press coverage — the fastest signal of what is happening at the AI research frontier.
Categories: cs.AI (Artificial Intelligence), cs.LG (Machine Learning), cs.CL (NLP), cs.CV (Computer Vision), cs.NE (Neural Computing), stat.ML.
Args: params (ArxivLatestInput): - categories (List[str]): arXiv category codes - limit (int): Papers per category (1–20)
Returns: str: JSON with categories, total_papers, by_category dict. Each paper: id, title, abstract (400 chars), authors, published, url, pdf.
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and idempotentHint. The description adds that papers appear before press coverage and lists categories, but does not discuss rate limits or auth needs, which is acceptable given annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is well-structured with an intro, context, category list, and Args/Returns sections. Slightly verbose but clear.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the output schema exists, the description still details return structure. It covers purpose, categories, parameters, and return format completely.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema already provides descriptions for parameters. The description's Args section repeats this info with no added meaning. Baseline 3 applies as schema coverage is sufficient.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool fetches the most recently submitted papers from arXiv AI/ML categories, specifying the resource and action. It lists the exact categories, distinguishing it from sibling tools like arxiv_search.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides context for use ('Papers appear hours before press coverage'), implying it's for early access. However, it does not explicitly state when not to use or contrast with alternatives like arxiv_search.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
arxiv_searchARead-onlyIdempotent
Search arXiv for papers matching a query, sorted by submission date.
Searches title, abstract and author fields. Optionally restrict to a specific AI/ML category.
Args: params (ArxivSearchInput): - query (str): Search terms (e.g. 'LLM agents tool use') - category (Optional[str]): arXiv category filter - limit (int): Papers to return (1–20)
Returns: str: JSON with query, category, count, papers[]. Each paper: id, title, abstract, authors, published, url, pdf.
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations (readOnlyHint, idempotentHint, destructiveHint) already indicate a safe read operation. The description adds value by specifying sorting order, searched fields, and optional category restriction, which goes beyond the annotations without contradiction.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is well-structured with a clear purpose statement, then parameter and return value documentation. It is slightly verbose due to the docstring format but remains concise and front-loaded with the main action.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's moderate complexity (3 parameters, simple search behavior), the combination of schema descriptions, annotations, and the description itself fully covers what the tool does, what parameters it expects, and what it returns. No gaps remain.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema already includes descriptions for all parameters (query, category, limit). The description repeats these details in a docstring format but adds no new semantic meaning beyond what the schema provides, resulting in a baseline score.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states it searches arXiv for papers matching a query, sorted by submission date, and specifies that it searches title, abstract, and author fields. This distinguishes it from sibling tools like arxiv_latest, which likely returns recent papers without a query.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description explains what the tool does but does not explicitly state when to use it versus alternatives like arxiv_latest or hn_search. Usage is implied for query-based searches, but no when-not or alternative guidance is provided.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
github_trending_aiARead-onlyIdempotent
Search GitHub for trending repositories by topic.
A surge of starred repos on a topic is a strong adoption signal. No auth required (60 req/h). Set GITHUB_TOKEN for 5,000 req/h.
Args: params (GithubTrendingAiInput): - topic (str): GitHub topic tag (e.g. 'llm', 'mcp', 'ai-agents') - limit (int): Repos to return (1–15) - min_stars (int): Minimum stars filter - sort (str): 'stars' or 'updated'
Returns: str: JSON with topic, total_found, count, repos[]. Each repo: name, description, stars, forks, language, topics, updated_at, url.
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate readOnlyHint, openWorldHint, idempotentHint, and non-destructive. The description adds significant value: rate limits per auth state, return format details (JSON structure with all fields), and that no auth is required. No contradictions.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is succinct and well-organized: purpose first, then context, then parameter list with args, finally return format. Every sentence adds value, no filler.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool has 4 parameters and an output schema, the description covers all aspects: what it does, when to use, auth, parameters with defaults, return shape. The return format is explicitly described, compensating for the output schema.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Although the input schema has descriptions for each property (contradicting the 0% coverage signal), the description's parameter block reinforces meanings with examples (e.g., topic 'llm', 'mcp') and clarifies sort options. It adds marginal value beyond the schema.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description starts with a clear verb and resource: 'Search GitHub for trending repositories by topic.' It distinguishes itself from sibling tools (arxiv, hn, lobsters, tech_signal_digest) by focusing on GitHub and trending topics, with a note about adoption signals.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides context on when to use (surge of starred repos as adoption signal) and includes rate limits and auth options. However, it lacks explicit when-not-to-use or direct alternatives, though sibling names imply different platforms.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
hn_discussionARead-onlyIdempotent
Read the comment thread under a HackerNews story.
Where hn_top_stories and hn_search tell you what is being discussed, this tells you what is actually being argued — the counter-arguments, the practitioner caveats, the "we tried this in production" replies that carry the real signal. Algolia can search comment text but does not return thread structure, so this is the only way to see who replied to whom.
Get a story_id from hn_top_stories or hn_search first.
Comments are walked breadth-first, so the highest-ranked top-level comments come back first. Deleted and flagged comments are skipped. Popular threads run to several hundred comments and each one costs a request upstream, so both depth and total count are capped — check the 'truncated' flag to see whether the thread was cut short.
Args: params (HnDiscussionInput): - story_id (int): HackerNews item ID - max_depth (int): Reply nesting levels (1–4, default 2) - max_comments (int): Total comment budget (1–100, default 25) - text_chars (int): Per-comment text truncation (100–2000)
Returns: str: JSON with story{}, total_comments (as reported by HN), fetched_comments, truncated, comments[]. Each comment: id, by, posted, text, reply_count, replies[] (same shape, nested).
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Beyond annotations (readOnly, idempotent), description details breadth-first walking, skipped comments, capping with truncated flag, and per-request cost.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Well-structured with purpose, rationale, usage, behavior, and parameter list; every sentence is substantive and no waste.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Covers output format, truncated flag, and capping logic; with output schema present, description provides sufficient context for correct invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Description lists all parameters with types and ranges, but essentially duplicates the input schema descriptions; adds no new meaning.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
Specifically states it reads HN comment thread structure, and distinguishes from siblings hn_top_stories (what's discussed) and hn_search (Algolia search without thread structure).
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Explicitly instructs to get a story_id from hn_top_stories or hn_search first, and explains when this tool is the only way to see thread structure versus alternatives.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
hn_searchARead-onlyIdempotent
Search HackerNews by keyword using the Algolia search API.
Covers all historical HN content. Find discussions on specific technologies, papers, companies, or events.
Args: params (HnSearchInput): - query (str): Search terms - limit (int): Results (1–20) - days_back (int): Recency window in days - tags (Optional[str]): 'story', 'ask_hn', 'show_hn', or empty
Returns: str: JSON with query, total_found, count, hits[]. Each hit: id, title, url, score, comments, author, posted, hn_link, excerpt.
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already provide readOnlyHint, idempotentHint, destructiveHint. The description adds valuable details: uses Algolia API, limits (1-20 results, 1-365 days back), and return structure (JSON with query, total_found, count, hits with fields). No contradictions with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is well-structured with an introductory sentence, scope statement, and formatted Args/Returns sections. It is appropriately sized, front-loaded with purpose, and each sentence adds value. Could be slightly more concise but overall efficient.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description covers purpose, parameters, return structure, and constraints. It does not include examples or error handling, but for a search tool, it is sufficiently complete given the output schema is also present. The Returns section compensates for the lack of explicit output schema in the provided input.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Input schema already provides good descriptions for all parameters. The description's Args section re-lists parameters with descriptions, adding minor clarity but not significant new information. Schema coverage is effectively high due to property descriptions, so baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool searches HackerNews via Algolia API, covering all historical content. It gives specific use cases (technologies, papers, companies, events). The sibling tool hn_top_stories likely provides current top stories, differentiating this tool.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description implies when to use the tool (searching all historical HN content for discussions). It does not explicitly state when not to use it or mention alternatives, but given siblings like hn_top_stories, users can infer appropriate usage. A brief mention of alternatives would improve clarity.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
hn_top_storiesARead-onlyIdempotent
Fetch stories from any of the six HackerNews front-page feeds.
Feeds: 'top' (frontpage), 'best' (highest voted), 'new' (latest), 'ask' (Ask HN — questions to the community), 'show' (Show HN — projects people are shipping), 'job' (YC company job posts).
'show' is the strongest signal for what practitioners are actually building; 'ask' for what they are stuck on. Upstream, 'ask' and 'job' hold only ~30 items, so a large limit may return fewer results.
Args: params (HnTopStoriesInput): - feed (str): 'top', 'best', 'new', 'ask', 'show', or 'job' - limit (int): Stories to return (1–30) - min_score (int): Minimum score filter (job posts score 1)
Returns: str: JSON with feed, count, stories[]. Each story: id, type, title, url, score, comments, by, posted, hn_link.
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations indicate readOnlyHint, idempotentHint, and destructiveHint false, which align with the read-only fetch. The description adds behavioral details like upstream feed length limits for 'ask' and 'job', and the return format including JSON structure.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Description is well-structured: purpose sentence, feed list with context, then parameter args, then return format. It is front-loaded with the core action and avoids redundancy, earning its sentences.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the existence of an output schema and annotations, the description fully explains the tool's behavior, parameters, feed semantics, and return structure, leaving no gaps for agent invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 0% (despite schema having descriptions), so the description must compensate. It explains each parameter (feed, limit, min_score) with context, including the cut-off note for 'ask' and 'job', adding value beyond the schema's own descriptions.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states it fetches stories from six HackerNews front-page feeds, lists each feed with a brief definition, and distinguishes from sibling tools like hn_search and hn_discussion by focusing on feed-based retrieval rather than search or discussion.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description provides context for when to use each feed (e.g., 'show' for practitioner projects, 'ask' for stuck issues) and notes that 'ask' and 'job' feeds are short. It does not explicitly exclude cases, but the sibling list and feed descriptions imply appropriate use.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
lobsters_hotARead-onlyIdempotent
Fetch the hottest stories from Lobste.rs, a curated tech community.
Lobste.rs is smaller and more technically focused than HackerNews. Invitation-only membership ensures higher signal-to-noise ratio.
Args: params (LobstersHotInput): - limit (int): Stories to return (1–25) - tag_filter (Optional[str]): Tag substring filter (e.g. 'ai', 'ml')
Returns: str: JSON with count, stories[]. Each story: title, url, score, comments, tags, submitter, submitted_at, lobsters_url.
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, covering the safety profile. The description adds background about the community but no new behavioral traits (like rate limits or caching). There is no contradiction with annotations.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
The description is front-loaded with the core purpose, followed by two sentences of context, and then a clear parameter list. Every sentence is informative and there is no fluff.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
The description fully explains what the tool does, its parameters, and the structure of its return value (including fields like title, url, score, etc.). Since an output schema exists, the return value details are sufficient. No gaps remain for this simple read-only tool.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Both parameters (limit and tag_filter) have descriptions in the input schema. The description repeats these details without adding new meaning. With high schema description coverage, the baseline score of 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states the tool fetches 'the hottest stories from Lobste.rs', a specific resource. It also provides context that Lobste.rs is smaller and more technically focused than HackerNews, which helps distinguish it from related tools like hn_top_stories.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description gives context by comparing Lobste.rs to HackerNews ('smaller and more technically focused'), implying when this tool might be preferred. However, it does not explicitly state when not to use it or name sibling alternatives directly.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
tech_signal_digestARead-onlyIdempotent
Aggregate tech & AI signals from all four sources in one call.
The primary tool for a comprehensive daily or weekly tech intelligence briefing. Combines HackerNews, arXiv, Lobste.rs and GitHub into one structured JSON digest. Use 'focus' to filter for a specific topic.
Args: params (TechSignalDigestInput): - focus (Optional[str]): Topic filter (e.g. 'MCP', 'agents') - hn_limit (int): HN stories (1–10) - arxiv_limit (int): arXiv papers (1–10) - lobsters_limit (int): Lobste.rs stories (1–10) - github_limit (int): GitHub repos (1–10)
Returns: str: JSON digest with generated_at, focus, sources{hn, arxiv, lobsters, github}. Each source has label, count, and its items list.
| Name | Required | Description | Default |
|---|---|---|---|
| params | Yes |
Output Schema
| Name | Required | Description |
|---|---|---|
| result | Yes |
TDQS
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already indicate read-only, idempotent, non-destructive behavior. Description adds that it combines sources and returns a structured JSON digest, enhancing transparency.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Description is concise, front-loaded with main purpose, and well-structured with clear Args and Returns sections.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
Given the tool's complexity and existing annotations/output schema, the description is complete enough to guide an agent in using the tool effectively.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema descriptions cover all parameters fully. Description repeats parameter info without adding novel semantics beyond what schema provides.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly states it aggregates tech signals from four sources into one digest, distinguishing it from sibling tools that focus on individual sources.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
Describes itself as the primary tool for daily/weekly briefings, implying use for broad overviews. Could explicitly mention when not to use, but sibling tool list provides context.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Tool Schema Changelog
Recent tool additions, removals, and schema changes observed during successful MCP inspections.
2 tool updates
v0.3.0- Added
hn_discussion - Changed
hn_top_stories2 fields changed- changed
Input schema / $defs / HnTopStoriesInput / properties / feed / descriptionPrevious value: -"Feed type: 'top' (frontpage), 'best' (highest voted), 'new' (latest)"New value: +"Feed type: 'top' (frontpage), 'best' (highest voted), 'new' (latest), 'ask' (Ask HN questions), 'show' (Show HN projects), 'job' (YC job posts). Note: 'ask' and 'job' are short feeds (~30 items upstream)." - changed
Input schema / $defs / HnTopStoriesInput / properties / feed / patternPrevious value: -"^(top|best|new)$"New value: +"^(top|best|new|ask|show|job)$"
7 tool updates
v0.2.4- First observed
arxiv_latest - First observed
arxiv_search - First observed
github_trending_ai - First observed
hn_search - First observed
hn_top_stories - First observed
lobsters_hot - First observed
tech_signal_digest
TDQS
Scored across 8 tools
Each tool targets a distinct source and operation: HN has separate tools for top stories, search, and discussion; arXiv has latest and search; Lobste.rs and GitHub each have one tool, and the digest aggregates all. No overlaps.
All tools follow a consistent `source_operation` pattern with lowercase and underscores (hn_top_stories, arxiv_latest, lobsters_hot, etc.), making them predictable and easy to navigate.
8 tools is well-scoped for a multi-source tech signal aggregator. Each source gets essential operations, and the digest tool integrates them, avoiding bloat or under-provisioning.
The tool set covers the core signal retrieval needs for each source: listing, searching, and detail extraction (comments, abstracts). The digest tool ties it together, leaving no obvious gaps for the stated purpose.
Maintenance
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