package github
import (
"os"
"slices"
"strings"
)
// GenerateInstructions creates server instructions based on enabled toolsets
func GenerateInstructions(enabledToolsets []string) string {
// For testing - add a flag to disable instructions
if os.Getenv("DISABLE_INSTRUCTIONS") == "true" {
return "" // Baseline mode
}
var instructions []string
// Core instruction - always included if context toolset enabled
if slices.Contains(enabledToolsets, "context") {
instructions = append(instructions, "Always call 'get_me' first to understand current user permissions and context.")
}
// Individual toolset instructions
for _, toolset := range enabledToolsets {
if inst := getToolsetInstructions(toolset, enabledToolsets); inst != "" {
instructions = append(instructions, inst)
}
}
// Base instruction with context management
baseInstruction := `The GitHub MCP Server provides tools to interact with GitHub platform.
Tool selection guidance:
1. Use 'list_*' tools for broad, simple retrieval and pagination of all items of a type (e.g., all issues, all PRs, all branches) with basic filtering.
2. Use 'search_*' tools for targeted queries with specific criteria, keywords, or complex filters (e.g., issues with certain text, PRs by author, code containing functions).
Context management:
1. Use pagination whenever possible with batches of 5-10 items.
2. Use minimal_output parameter set to true if the full information is not needed to accomplish a task.
Tool usage guidance:
1. For 'search_*' tools: Use separate 'sort' and 'order' parameters if available for sorting results - do not include 'sort:' syntax in query strings. Query strings should contain only search criteria (e.g., 'org:google language:python'), not sorting instructions.`
allInstructions := []string{baseInstruction}
allInstructions = append(allInstructions, instructions...)
return strings.Join(allInstructions, " ")
}
// getToolsetInstructions returns specific instructions for individual toolsets
func getToolsetInstructions(toolset string, enabledToolsets []string) string {
switch toolset {
case "pull_requests":
pullRequestInstructions := `## Pull Requests
PR review workflow: Always use 'pull_request_review_write' with method 'create' to create a pending review, then 'add_comment_to_pending_review' to add comments, and finally 'pull_request_review_write' with method 'submit_pending' to submit the review for complex reviews with line-specific comments.`
if slices.Contains(enabledToolsets, "repos") {
pullRequestInstructions += `
Before creating a pull request, search for pull request templates in the repository. Template files are called pull_request_template.md or they're located in '.github/PULL_REQUEST_TEMPLATE' directory. Use the template content to structure the PR description and then call create_pull_request tool.`
}
return pullRequestInstructions
case "issues":
return `## Issues
Check 'list_issue_types' first for organizations to use proper issue types. Use 'search_issues' before creating new issues to avoid duplicates. Always set 'state_reason' when closing issues.`
case "discussions":
return `## Discussions
Use 'list_discussion_categories' to understand available categories before creating discussions. Filter by category for better organization.`
case "projects":
return `## Projects
Workflow: 1) list_project_fields (get field IDs), 2) list_project_items (with pagination), 3) optional updates.
Field usage:
- Call list_project_fields first to understand available fields and get IDs/types before filtering.
- Use EXACT returned field names (case-insensitive match). Don't invent names or IDs.
- Iteration synonyms (sprint/cycle) only if that field exists; map to the actual name (e.g. sprint:@current).
- Only include filters for fields that exist and are relevant.
Pagination (mandatory):
- Loop while pageInfo.hasNextPage=true using after=pageInfo.nextCursor.
- Keep query, fields, per_page IDENTICAL on every page.
- Use before=pageInfo.prevCursor only when explicitly navigating to a previous page.
Counting rules:
- Count items array length after full pagination.
- Never count field objects, content, or nested arrays as separate items.
Summary vs list:
- Summaries ONLY if user uses verbs: analyze | summarize | summary | report | overview | insights.
- Listing verbs (list/show/get/fetch/display/enumerate) → enumerate + total.
Self-check before returning:
- Paginated fully
- Correct IDs used
- Field names valid
- Summary only if requested.
Return COMPLETE data or state what's missing (e.g. pages skipped).
list_project_items query rules:
Query string - For advanced filtering of project items using GitHub's project filtering syntax:
MUST reflect user intent; strongly prefer explicit content type if narrowed:
- "open issues" → state:open is:issue
- "merged PRs" → state:merged is:pr
- "items updated this week" → updated:>@today-7d (omit type only if mixed desired)
- "list all P1 priority items" → priority:p1 (omit state if user wants all, omit type if user specifies "items")
- "list all open P2 issues" → is:issue state:open priority:p2 (include state if user wants open or closed, include type if user specifies "issues" or "PRs")
- "all open issues I'm working on" → is:issue state:open assignee:@me
Query Construction Heuristics:
a. Extract type nouns: issues → is:issue | PRs, Pulls, or Pull Requests → is:pr | tasks/tickets → is:issue (ask if ambiguity)
b. Map temporal phrases: "this week" → updated:>@today-7d
c. Map negations: "excluding wontfix" → -label:wontfix
d. Map priority adjectives: "high/sev1/p1" → priority:high OR priority:p1 (choose based on field presence)
e. When filtering by label, always use wildcard matching to account for cross-repository differences or emojis: (e.g. "bug 🐛" → label:*bug*)
f. When filtering by milestone, always use wildcard matching to account for cross-repository differences: (e.g. "v1.0" → milestone:*v1.0*)
Syntax Essentials (items):
AND: space-separated. (label:bug priority:high).
OR: comma inside one qualifier (label:bug,critical).
NOT: leading '-' (-label:wontfix).
Hyphenate multi-word field names. (team-name:"Backend Team", story-points:>5).
Quote multi-word values. (status:"In Review" team-name:"Backend Team").
Ranges: points:1..3, updated:<@today-30d.
Wildcards: title:*crash*, label:bug*.
Assigned to User: assignee:@me | assignee:username | no:assignee
Common Qualifier Glossary (items):
is:issue | is:pr | state:open|closed|merged | assignee:@me|username | label:NAME | status:VALUE |
priority:p1|high | sprint-name:@current | team-name:"Backend Team" | parent-issue:"org/repo#123" |
updated:>@today-7d | title:*text* | -label:wontfix | label:bug,critical | no:assignee | has:label
Never:
- Infer field IDs; fetch via list_project_fields.
- Drop 'fields' param on subsequent pages if field values are needed.`
default:
return ""
}
}
