Add twchat toolset for Teamwork Chat

[4ver]

Summary

Adds a new twchat toolset exposing basic Teamwork Chat support, alongside the existing twprojects, twspaces, and twdesk toolsets.

The Chat API is served at /chat/v7/... on the same installation host as the Projects API and authenticates with the same bearer token, so these tools ride the existing twapi.Engine via custom HTTPRequester types and stream the raw JSON response through twapi.ExecuteRaw. No new SDK dependency or config is required.

Tools

Six tools under one sub-toolset (twchat-chat) — 5 read + 1 write (send_message is gated automatically by read-only mode):

Tool	Endpoint
twchat-get_current_user	GET /chat/v7/me
twchat-list_conversations	GET /chat/v7/conversations
twchat-get_conversation	GET /chat/v7/conversations/:id
twchat-list_messages	GET /chat/v7/conversations/:id/messages
twchat-list_people	GET /chat/v7/people
twchat-send_message	POST /chat/v7/conversations/:id/messages

Implementation

• New package internal/twchat/: tools.go (registration + DefaultToolsetGroup), requests.go (the HTTPRequester types), chat.go (tool constructors + shared execute helper).
• Registered the group in cmd/mcp-stdio/main.go and cmd/mcp-http/main.go.
• Added testutil.ChatMCPServerMock (reuses the existing ProjectsEngineMock) plus one test per tool.
• Output is raw JSON passthrough (no typed structs / output schemas), matching the twprojects budget/list pattern.

Verification

gofmt -s, go build ./..., go vet ./..., and go test ./... all pass; the new twchat tests are green.

Out of scope (future)

Reactions, starring, conversation create/update/leave, attachments/file upload, and message edit/delete — easy follow-ups on the same pattern.

[rafaeljusto]

There's also some tool filtering depending on what scope your token allows here:

mcp/internal/config/config.go

Lines 252 to 260 in dc4158f

	projectsScope := slices.Contains(scopes, "projects")
	deskScope := slices.Contains(scopes, "desk")
	spacesScope := slices.Contains(scopes, "spaces")
	listToolsResult.Tools = slices.DeleteFunc(listToolsResult.Tools, func(tool *mcp.Tool) bool {
	return (strings.HasPrefix(tool.Name, "twprojects") && !projectsScope) ||
	(strings.HasPrefix(tool.Name, "twdesk") && !deskScope) ||
	(strings.HasPrefix(tool.Name, "twspaces") && !spacesScope)
	})

[tw-garymeehan]

All non-blocking.

Reviewed by Claude against some token optimisation work we've done recently 🤖

Token-count review (scoped to tool/param descriptions) — summary to go with the two inline notes above.

Verdict: lean and on-convention — not a bloat problem. Measured with cmd/mcp-tokens (tiktoken o200k_base): the 8 twchat tools add 1,049 tokens / ~2.6% to the registry, and the list tools are actually cheaper than comparable helper-based ones (list_messages 295 / list_conversations 266 vs twprojects-list_comments 405).

Two things worth addressing:

1. cmd/mcp-tokens isn't updated to include twchat. allGroups() (cmd/mcp-tokens/main.go:108-112) lists only twprojects + twdesk + twspaces, so the token-budget tracker from Add mcp-tokens command to measure tool token costs #300 is blind to these ~1,049 tokens and every future -base=main delta silently omits them. Fix is one line: add twchat.DefaultToolsetGroup(false, nil) to allGroups() (plus the import).

2. Shared schema helpers aren't reused — see the two inline comments on internal/twchat/chat.go (search-term / pagination / date-time filters already exist in internal/helpers/schema.go from Refactor: Add shared schema helpers for pagination, tag, and search params #306).

[4ver]

Still have to test. Okay to chuck it onto staging to give it a go?

[rafaeljusto]

Still have to test. Okay to chuck it onto staging to give it a go?

Fire away. Changes should trigger a build once merged to the staging branch.