# Feature Specification: HackerNews MCP Server
**Feature Branch**: `001-hn-mcp-server`
**Created**: October 30, 2025
**Status**: Draft
**Input**: User description: "Create a HackerNews MCP server for interacting with HackerNews API at https://hn.algolia.com/api . Users should be able to search for posts, find latest posts on the front page, and all other capabilities exposed by the API"
## User Scenarios & Testing *(mandatory)*
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IMPORTANT: User stories should be PRIORITIZED as user journeys ordered by importance.
Each user story/journey must be INDEPENDENTLY TESTABLE - meaning if you implement just ONE of them,
you should still have a viable MVP (Minimum Viable Product) that delivers value.
Assign priorities (P1, P2, P3, etc.) to each story, where P1 is the most critical.
Think of each story as a standalone slice of functionality that can be:
- Developed independently
- Tested independently
- Deployed independently
- Demonstrated to users independently
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### User Story 1 - Search HackerNews Posts (Priority: P1)
As a developer or AI agent using the MCP server, I want to search for HackerNews posts by keywords so that I can find relevant discussions and articles on specific topics.
**Why this priority**: Search is the core capability that provides immediate value. Users can discover content based on their interests without needing to know specific post IDs or authors.
**Independent Test**: Can be fully tested by performing a keyword search (e.g., "artificial intelligence") and verifying that relevant HackerNews stories are returned with key metadata (title, URL, author, points, comments count).
**Acceptance Scenarios**:
1. **Given** I want to find posts about Python, **When** I search with query "Python", **Then** I receive a list of matching posts with titles, URLs, authors, points, and comment counts
2. **Given** I want recent posts about a topic, **When** I search with date-sorted results, **Then** I receive posts ordered by most recent first
3. **Given** I want only stories (not comments), **When** I filter search by content type "story", **Then** I receive only story-type posts matching my query
4. **Given** I want highly-ranked content, **When** I search with minimum points filter (e.g., >100 points), **Then** I receive only posts exceeding that threshold
5. **Given** the search returns many results, **When** I request a specific page of results, **Then** I receive the requested page with pagination metadata
---
### User Story 2 - View Front Page Content (Priority: P2)
As a developer or AI agent, I want to retrieve current front page posts so that I can see what topics are trending and popular in the HackerNews community right now.
**Why this priority**: Front page viewing is a fundamental use case that mirrors the primary HackerNews experience. It requires no user input beyond the request itself, making it simple to implement and test.
**Independent Test**: Can be fully tested by requesting front page posts and verifying that returned items match what appears on the actual HackerNews front page, including proper ordering and metadata.
**Acceptance Scenarios**:
1. **Given** I want to see trending content, **When** I request front page posts, **Then** I receive currently featured posts with ranking, titles, URLs, authors, points, and comment counts
2. **Given** I want to browse front page content, **When** I paginate through results, **Then** I can navigate through multiple pages of front page items
---
### User Story 3 - Retrieve Post Details (Priority: P3)
As a developer or AI agent, I want to retrieve full details of a specific post by its ID so that I can access complete information including the full comment tree.
**Why this priority**: Detailed post viewing builds on search and discovery capabilities. While important for deep dives, users first need to discover posts (P1/P2) before viewing details.
**Independent Test**: Can be fully tested by requesting a known post ID and verifying all details are returned including nested comment threads with proper hierarchy.
**Acceptance Scenarios**:
1. **Given** I have a post ID, **When** I request that post's details, **Then** I receive the complete post data including title, URL, author, text content, points, and full comment tree
2. **Given** I want to see discussion, **When** I retrieve a post with comments, **Then** I receive all comments in hierarchical structure with author, text, points, and timestamps
3. **Given** I want to understand engagement, **When** I view post details, **Then** I see creation timestamp, current points, and number of comments
---
### User Story 4 - Get User Information (Priority: P4)
As a developer or AI agent, I want to retrieve user profile information so that I can learn about content creators and their contribution history on HackerNews.
**Why this priority**: User profiles provide context about content creators but are secondary to content discovery and viewing. Useful for credibility assessment and author research.
**Independent Test**: Can be fully tested by requesting a known username and verifying profile data (karma, about text, created date) is returned accurately.
**Acceptance Scenarios**:
1. **Given** I want to learn about a user, **When** I request their username, **Then** I receive their profile including karma score, about/bio text, and account creation date
2. **Given** I see an interesting author, **When** I search for their posts, **Then** I can filter search results to show only that author's contributions
---
### User Story 5 - Advanced Search Filtering (Priority: P5)
As a developer or AI agent, I want to apply multiple filters simultaneously so that I can perform sophisticated queries combining content type, author, date ranges, and numeric thresholds.
**Why this priority**: Advanced filtering enables power users to perform complex queries but requires basic search (P1) to be functional first. These are refinement capabilities.
**Independent Test**: Can be fully tested by combining multiple filter parameters (e.g., author + content type + date range) and verifying results match all specified criteria.
**Acceptance Scenarios**:
1. **Given** I want posts by a specific author, **When** I filter by username, **Then** I receive only posts authored by that user
2. **Given** I want content from a time period, **When** I specify date range filters, **Then** I receive only posts created within that timeframe
3. **Given** I want to combine filters, **When** I specify author AND content type AND minimum points, **Then** I receive only posts matching all criteria
4. **Given** I want stories or polls, **When** I use OR logic for content types, **Then** I receive posts matching any of the specified types
---
### Edge Cases
- What happens when a search query returns no results?
- How does the system handle invalid post IDs?
- What occurs when requesting a user that doesn't exist?
- How are rate limits (10,000 requests per hour per IP) communicated to users?
- What happens when pagination exceeds available pages?
- How does the system handle special characters or very long search queries?
- What occurs when the HackerNews API is unavailable or returns errors?
- How are deleted posts or [dead] flagged content handled?
## Requirements *(mandatory)*
### Functional Requirements
- **FR-001**: System MUST provide search capability accepting text queries and returning matching HackerNews content
- **FR-002**: System MUST support filtering search results by content type (story, comment, poll, pollopt, show_hn, ask_hn)
- **FR-003**: System MUST support filtering search results by author username
- **FR-004**: System MUST support filtering search results by numeric conditions (creation date, points, comment count)
- **FR-005**: System MUST enable retrieval of current front page posts
- **FR-006**: System MUST allow retrieval of specific posts by their unique ID
- **FR-007**: System MUST provide access to full comment trees for posts with nested hierarchy preserved
- **FR-008**: System MUST allow retrieval of user profile information by username
- **FR-009**: System MUST support pagination for search results with configurable page size
- **FR-010**: System MUST support date-sorted search results (most recent first)
- **FR-011**: System MUST support relevance-sorted search results (by relevance, then points, then comments)
- **FR-012**: System MUST support combining multiple filters with AND logic by default
- **FR-013**: System MUST support OR logic for filters when specified (e.g., multiple content types)
- **FR-014**: System MUST return post metadata including title, URL, author, points, comment count, creation timestamp, and text content when available
- **FR-015**: System MUST return user profile data including username, karma score, about text, and account creation date
- **FR-016**: System MUST handle API errors gracefully and communicate error states to users
- **FR-017**: System MUST respect HackerNews API rate limits (10,000 requests per hour per IP)
- **FR-018**: System MUST provide feedback when searches return no results
- **FR-019**: System MUST validate user inputs (post IDs, usernames, filter parameters) before making API requests
### Key Entities *(include if feature involves data)*
- **HackerNews Post**: Represents any item on HackerNews (story, comment, poll, etc.) with attributes: unique ID, creation timestamp, author, title (for stories), URL (for stories), text content, points, parent post ID (for comments), list of child comments
- **HackerNews User**: Represents a HackerNews community member with attributes: username, karma score, about/bio text, account creation date
- **Search Query**: Represents a user's search request with attributes: search terms, content type filters, author filters, numeric filters (date range, minimum points, comment count), sort order, pagination parameters (page number, results per page)
- **Search Result**: Represents the response from a search with attributes: list of matching posts, total result count, total page count, current page number, results per page, processing time
- **Comment Tree**: Represents the hierarchical structure of comments on a post with recursive parent-child relationships
## Success Criteria *(mandatory)*
### Measurable Outcomes
- **SC-001**: Users can successfully search for HackerNews posts and receive relevant results in under 3 seconds
- **SC-002**: Users can retrieve front page posts matching the current HackerNews front page with 100% accuracy
- **SC-003**: Users can access complete comment trees for any post with all nested relationships preserved
- **SC-004**: System successfully handles at least 95% of valid API requests without errors
- **SC-005**: System provides clear error messages for all error conditions (invalid IDs, missing users, API failures) enabling users to understand and recover from errors
- **SC-006**: Users can combine multiple search filters (e.g., author + content type + date range) and receive accurate results matching all criteria
- **SC-007**: System respects HackerNews API rate limits and never exceeds 10,000 requests per hour per IP
- **SC-008**: All search results include complete metadata (title, author, points, comments, timestamps) enabling users to evaluate content without additional requests
- **SC-009**: 90% of common search and retrieval operations complete successfully on first attempt without requiring clarification or retry
- **SC-010**: System handles pagination correctly allowing users to navigate through large result sets without missing or duplicate items
