fix(task_list): list all tasks by default and add list_lists action

[Cstewart-HC]

Fixes #776

Problem

When task_list.list was called without specifying list_id, it defaulted to "default". Tasks created under custom list IDs (e.g. "CURRICULUM_1") were invisible unless the agent explicitly knew to pass that ID. There was also no way to discover what lists existed.

Changes

• Omitting list_id on list action now defaults to "*" (all lists) instead of "default". Explicitly passing list_id="default" still scopes to that list only.
• Wildcard list_id="*" queries across every known list.
• New list_lists action returns all known list IDs by scanning persisted JSON files, filtering out phantom empty lists.
• Task struct gains list_id field — always populated on creation, enabling agents to issue follow-up get/update/claim from cross-list query results. Forward-compatible with legacy files via #[serde(default)].
• TaskStore gains list_ids() and list_all_tasks() methods.
• Schema and description updated to document all new behavior.
• Cross-list sort uses (list_id, numeric_id) tuple for stable ordering.

Testing

7 new tests (11 total), all passing:

• list_without_list_id_returns_all_tasks — omit sees all lists
• list_with_wildcard_returns_all_tasks — explicit * sees all lists
• list_lists_returns_all_known_ids — discovers list IDs
• explicit_default_list_id_still_scopes — explicit default still scopes
• wildcard_list_includes_list_id_field — cross-list tasks carry list_id
• single_list_includes_list_id_field — single-list tasks carry list_id
• list_lists_excludes_phantom_empty_lists — no phantom lists

Validation

• cargo fmt --check ✅
• cargo clippy -D warnings ✅ (on moltis-tools)
• cargo test -p moltis-tools --lib task_list ✅ 11/11

Blast Radius

Single-file change (crates/tools/src/task_list.rs). No other crate imports Task, TaskList, TaskStore, or TaskStatus. The TaskListTool::new() constructor signature is unchanged. Persisted JSON is forward-compatible.

[greptile-apps]

Greptile Summary

This PR fixes invisible cross-list tasks by changing the default list behaviour from scoping to "default" to querying all lists ("*"), adds a list_lists discovery action, and gives every Task a list_id field so wildcard results can drive follow-up get/update/claim calls. The prior review's three concerns (missing list_id on tasks, phantom lists appearing in list_ids, and unresolved TOCTOU notes) have each been addressed or explicitly acknowledged in the code.

Confidence Score: 5/5

Safe to merge; all P0/P1 concerns from prior review rounds are resolved, remaining findings are P2 style issues.

The three issues from the previous review threads (missing list_id on wildcard tasks, phantom lists in list_ids, and sort allocation) are addressed. The two new findings are P2: blocking Path::exists() inside an async lock (a latency concern, not a correctness bug at this scale) and the missing legacy-task backfill in the single-list path (the wildcard cross-list path — the primary use case — is correctly handled). Neither blocks merge.

crates/tools/src/task_list.rs — list_ids filter and single-list list_tasks return path

Important Files Changed

Filename	Overview
crates/tools/src/task_list.rs	Adds list_ids(), list_all_tasks(), wildcard list_tasks dispatch, list_lists action, and Task.list_id field; 7 new tests cover all new paths. Two minor issues: synchronous Path::exists() called while holding the RwLock read guard, and the single-list list_tasks path doesn't backfill list_id for legacy tasks unlike list_all_tasks.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[execute params] --> B{action?}
    B -->|list| C{list_id provided?}
    C -->|no / omitted| D[effective_id = '*']
    C -->|explicit value| E[effective_id = list_id]
    D --> F{list_id == '*'?}
    E --> F
    F -->|yes| G[list_all_tasks]
    F -->|no| H[list_tasks single list]
    G --> I[list_ids: scan disk + filter phantoms]
    I --> J[read lock: collect + backfill list_id]
    J --> K[sort by list_id, numeric_id]
    H --> L[ensure_list]
    L --> M[read lock: filter + sort]
    M --> N[⚠️ list_id not backfilled for legacy tasks]
    B -->|list_lists| O[list_ids]
    O --> P[return sorted list IDs]
    B -->|create| Q[ensure_list + write + persist]
    Q --> R[Task with list_id set]
    B -->|get / update / claim| S[ensure_list + write lock]

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[Cstewart-HC]

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