Reduce context usage for list_pull_requests

[kerobbi]

Summary

Reduces context usage for list_pull_requests by using the existing MinimalPullRequest type.

Fields preserved / dropped

Same as #2017, as it uses the same MinimalPullRequest type introduced there for get_pull_request.

Token Reduction

Measured using a script that makes use of OAI's tiktoken library (o200k_base) at 2 and 100 items. The web version can be found here.

Items	Baseline	Optimised	Reduction
2	11,779	1,657	85.9%
100	657, 272	153,352	76.7%

Why

list_pull_requests was returning raw *github.PullRequest objects with ~40+ fields including nested user objects, API URLs, node IDs, etc.. Most of this is noise not useful for model reasoning.

What changed

• Wired convertToMinimalPullRequest in list_pull_requests
• Updated relevant tests

MCP impact

• No tool or API changes
• Tool schema or behavior changed
• New tool added

Prompts tested (tool changes only)

• List the last 2 PRs in github/github-mcp-server
• List the last 100 PRs in github/github-mcp-server

Security / limits

• No security or limits impact
• Auth / permissions considered
• Data exposure, filtering, or token/size limits considered

Tool renaming

• I am renaming tools as part of this PR (e.g. a part of a consolidation effort)
  • I have added the new tool aliases in deprecated_tool_aliases.go
• I am not renaming tools as part of this PR

Note: if you're renaming tools, you must add the tool aliases. For more information on how to do so, please refer to the official docs.

Lint & tests

• Linted locally with ./script/lint
• Tested locally with ./script/test

Docs

• Not needed
• Updated (README / docs / examples)

[Copilot]

Pull request overview

This PR reduces context usage for the list_pull_requests tool by up to 85.9% (2 items) and 76.7% (100 items) by using the existing MinimalPullRequest type introduced in PR #2017. The change converts the tool output from raw *github.PullRequest objects with 40+ fields to streamlined MinimalPullRequest objects that preserve only essential fields for model reasoning while dropping verbose API metadata and nested objects.

Changes:

• Converted list_pull_requests output from []*github.PullRequest to []MinimalPullRequest using existing convertToMinimalPullRequest function
• Updated test assertions to work with non-pointer field values in MinimalPullRequest

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
pkg/github/pullrequests.go	Added conversion loop to transform PR list to MinimalPullRequest slice before marshaling
pkg/github/pullrequests_test.go	Updated assertions to compare non-pointer MinimalPullRequest fields directly instead of dereferencing pointers

[tommaso-moro]

🚀