hn-tech-signal-mcp

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tech_signal_digest

Read-onlyIdempotent

Aggregate HackerNews, arXiv, Lobste.rs and GitHub tech signals into one JSON digest, filtered by topic for daily or weekly briefings.

Instructions

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, degraded_sources[] and sources{hn, arxiv, lobsters, github}. Each source has label, count and its items list.

     A source that could not be reached still appears, with count 0
     and an 'error' describing why, and its key is listed in
     degraded_sources — treat its absence as unknown, not as zero.
     The GitHub section may carry 'incomplete_topics' when part of
     the topic sweep failed. Only if all four sources fail does this
     tool return a plain error string instead of JSON.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`params`	Yes

Output Schema

TableJSON Schema

Name	Required	Description
`focus`	Yes
`sources`	Yes
`generated_at`	Yes
`degraded_sources`	Yes	Sources that failed; treat their sections as unknown, not as empty

Schema Changelog

Changes observed during successful MCP inspections.

Changed9 schema fields changedv0.5.0Sep 30, 2026

addedOutput schema / $defs

Added value: +{
+  "ArxivPaper": {
+    "additionalProperties": false,
+    "properties": {
+      "abstract": {
+        "description": "First 400 characters",
+        "title": "Abstract",
+        "type": "string"
+      },
+      "authors": {
+        "description": "First five",
+        "items": {
+          "type": "string"
+        },
+        "title": "Authors",
+        "type": "array"
+      },
+      "categories": {
+        "description": "All categories, primary included",
+        "items": {
+          "type": "string"
+        },
+        "title": "Categories",
+        "type": "array"
+      },
+      "category": {
+        "description": "Primary category",
+        "title": "Category",
+        "type": "string"
+      },
+      "id": {
+        "title": "Id",
+        "type": "string"
+      },
+      "pdf": {
+        "title": "Pdf",
+        "type": "string"
+      },
+      "published": {
+        "title": "Published",
+        "type": "string"
+      },
+      "title": {
+        "title": "Title",
+        "type": "string"
+      },
+      "url": {
+        "title": "Url",
+        "type": "string"
+      }
+    },
+    "required": [
+      "id",
+      "title",
+      "abstract",
+      "authors",
+      "published",
+      "category",
+      "categories",
+      "url",
+      "pdf"
+    ],
+    "title": "ArxivPaper",
+    "type": "object"
+  },
+  "DigestArxivSection": {
+    "additionalProperties": false,
+    "properties": {
+      "count": {
+        "title": "Count",
+        "type": "integer"
+      },
+      "error": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "default": null,
+        "description": "Present only when the source failed; count is then 0 and means unknown",
+        "title": "Error"
+      },
+      "label": {
+        "title": "Label",
+        "type": "string"
+      },
+      "papers": {
+        "items": {
+          "$ref": "#/$defs/ArxivPaper"
+        },
+        "title": "Papers",
+        "type": "array"
+      }
+    },
+    "required": [
+      "label",
+      "count",
+      "papers"
+    ],
+    "title": "DigestArxivSection",
+    "type": "object"
+  },
+  "DigestGithubRepo": {
+    "additionalProperties": false,
+    "properties": {
+      "description": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Description"
+      },
+      "language": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Language"
+      },
+      "name": {
+        "title": "Name",
+        "type": "string"
+      },
+      "stars": {
+        "anyOf": [
+          {
+            "type": "integer"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Stars"
+      },
+      "topics": {
+        "anyOf": [
+          {
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Topics"
+      },
+      "url": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Url"
+      }
+    },
+    "required": [
+      "name",
+      "description",
+      "stars",
+      "language",
+      "topics",
+      "url"
+    ],
+    "title": "DigestGithubRepo",
+    "type": "object"
+  },
+  "DigestGithubSection": {
+    "additionalProperties": false,
+    "properties": {
+      "count": {
+        "title": "Count",
+        "type": "integer"
+      },
+      "error": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "default": null,
+        "description": "Present only when the source failed; count is then 0 and means unknown",
+        "title": "Error"
+      },
+      "incomplete_topics": {
+        "anyOf": [
+          {
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "default": null,
+        "description": "Topics whose sweep failed; the section is short by them",
+        "title": "Incomplete Topics"
+      },
+      "label": {
+        "title": "Label",
+        "type": "string"
+      },
+      "repos": {
+        "items": {
+          "$ref": "#/$defs/DigestGithubRepo"
+        },
+        "title": "Repos",
+        "type": "array"
+      }
+    },
+    "required": [
+      "label",
+      "count",
+      "repos"
+    ],
+    "title": "DigestGithubSection",
+    "type": "object"
+  },
+  "DigestHnSection": {
+    "additionalProperties": false,
+    "properties": {
+      "count": {
+        "title": "Count",
+        "type": "integer"
+      },
+      "error": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "default": null,
+        "description": "Present only when the source failed; count is then 0 and means unknown",
+        "title": "Error"
+      },
+      "label": {
+        "title": "Label",
+        "type": "string"
+      },
+      "stories": {
+        "items": {
+          "$ref": "#/$defs/HnStory"
+        },
+        "title": "Stories",
+        "type": "array"
+      }
+    },
+    "required": [
+      "label",
+      "count",
+      "stories"
+    ],
+    "title": "DigestHnSection",
+    "type": "object"
+  },
+  "DigestLobstersSection": {
+    "additionalProperties": false,
+    "properties": {
+      "count": {
+        "title": "Count",
+        "type": "integer"
+      },
+      "error": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "default": null,
+        "description": "Present only when the source failed; count is then 0 and means unknown",
+        "title": "Error"
+      },
+      "label": {
+        "title": "Label",
+        "type": "string"
+      },
+      "stories": {
+        "items": {
+          "$ref": "#/$defs/DigestLobstersStory"
+        },
+        "title": "Stories",
+        "type": "array"
+      }
+    },
+    "required": [
+      "label",
+      "count",
+      "stories"
+    ],
+    "title": "DigestLobstersSection",
+    "type": "object"
+  },
+  "DigestLobstersStory": {
+    "additionalProperties": false,
+    "properties": {
+      "lobsters_url": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Lobsters Url"
+      },
+      "score": {
+        "anyOf": [
+          {
+            "type": "integer"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Score"
+      },
+      "tags": {
+        "anyOf": [
+          {
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Tags"
+      },
+      "title": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Title"
+      },
+      "url": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Url"
+      }
+    },
+    "required": [
+      "title",
+      "url",
+      "score",
+      "tags",
+      "lobsters_url"
+    ],
+    "title": "DigestLobstersStory",
+    "type": "object"
+  },
+  "DigestSources": {
+    "additionalProperties": false,
+    "properties": {
+      "arxiv": {
+        "$ref": "#/$defs/DigestArxivSection"
+      },
+      "github": {
+        "$ref": "#/$defs/DigestGithubSection"
+      },
+      "hn": {
+        "$ref": "#/$defs/DigestHnSection"
+      },
+      "lobsters": {
+        "$ref": "#/$defs/DigestLobstersSection"
+      }
+    },
+    "required": [
+      "hn",
+      "arxiv",
+      "lobsters",
+      "github"
+    ],
+    "title": "DigestSources",
+    "type": "object"
+  },
+  "HnStory": {
+    "additionalProperties": false,
+    "properties": {
+      "by": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "By"
+      },
+      "comments": {
+        "title": "Comments",
+        "type": "integer"
+      },
+      "hn_link": {
+        "title": "Hn Link",
+        "type": "string"
+      },
+      "id": {
+        "anyOf": [
+          {
+            "type": "integer"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Id"
+      },
+      "posted": {
+        "description": "UTC timestamp, or 'unknown'",
+        "title": "Posted",
+        "type": "string"
+      },
+      "score": {
+        "title": "Score",
+        "type": "integer"
+      },
+      "title": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "title": "Title"
+      },
+      "type": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "type": "null"
+          }
+        ],
+        "description": "'story' or 'job'",
+        "title": "Type"
+      },
+      "url": {
+        "description": "Linked article, or the HN item itself for Ask HN",
+        "title": "Url",
+        "type": "string"
+      }
+    },
+    "required": [
+      "id",
+      "type",
+      "title",
+      "url",
+      "score",
+      "comments",
+      "by",
+      "posted",
+      "hn_link"
+    ],
+    "title": "HnStory",
+    "type": "object"
+  }
+}

addedOutput schema / additionalProperties
```
Added value: +false
```

addedOutput schema / properties / degraded_sources

Added value: +{
+  "description": "Sources that failed; treat their sections as unknown, not as empty",
+  "items": {
+    "type": "string"
+  },
+  "title": "Degraded Sources",
+  "type": "array"
+}

addedOutput schema / properties / focus

Added value: +{
+  "title": "Focus",
+  "type": "string"
+}

addedOutput schema / properties / generated_at

Added value: +{
+  "title": "Generated At",
+  "type": "string"
+}

removedOutput schema / properties / result

Removed value: -{
-  "title": "Result",
-  "type": "string"
-}

addedOutput schema / properties / sources

Added value: +{
+  "$ref": "#/$defs/DigestSources"
+}

changedOutput schema / required

Previous value: -[
-  "result"
-]New value: +[
+  "generated_at",
+  "focus",
+  "degraded_sources",
+  "sources"
+]

changedOutput schema / title

Previous value: -"tech_signal_digestOutput"New value: +"TechSignalDigestOutput"

First observedv0.2.4Jul 11, 2026

TDQS

A4.6/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover readOnly/idempotent/open-world, so the description correctly spends its budget on non-obvious behavior: partial-failure semantics (a failed source still appears with count 0, an error, and a degraded_sources entry, which must be read as 'unknown, not zero'), incomplete_topics on the GitHub sweep, and the all-fail plain-error-string case. This is exactly the failure-mode context annotations cannot convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The summary and routing sentence are front-loaded and zero-waste. The Args/Returns blocks are longer than strictly necessary, but each line (ranges, degraded-source handling) carries actionable information rather than filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Even though an output schema exists, the description adds the degraded_sources and incomplete_topics contract that an agent needs to interpret the JSON correctly, plus the fallback error-string case. Nothing needed to call or interpret this tool correctly appears to be missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is reported as 0%, so the description must carry the parameter burden: it lists focus (with examples 'MCP', 'agents'), and all four limit params with their 1–10 bounds. It omits the default of 5 and does not clarify the empty-string focus case, so it compensates well but not completely.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The first line states a specific verb+resource ('aggregate tech & AI signals from all four sources') and names the four sources explicitly. It clearly distinguishes itself from siblings like hn_top_stories or arxiv_latest, which cover only one source each.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It states the primary use case ('daily or weekly tech intelligence briefing') and the focus-filter variant, which implicitly steers narrow single-source needs to the hn_/arxiv_/lobsters_/github_ siblings. It never says when NOT to use it or names a sibling explicitly, so a 4 rather than 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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