Set Active Project

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full behavioral burden, and it only discloses that a marker file is written to the data root. It never says whether an existing marker is overwritten, whether project_id must already exist, whether the write persists across sessions, or what permissions are needed.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single short sentence with no waste and the action front-loaded, but its brevity comes at the cost of substance rather than from tight editing — it is terse, not efficient.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

This is a state-mutating tool with no annotations and no output schema, so the description should explain at minimum what state changes and any preconditions. It omits both, leaving an agent unable to predict the effect on prior project state.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% — both project_id and narrative_data_root (including its NARRATIVE_DATA_ROOT default) are documented in the schema. The description adds no parameter meaning beyond that, so the baseline of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a concrete verb and resource ('写入数据根 .active-project 标记文件'), so the mechanism is inferable, but it never actually states the purpose — setting the active project — and does nothing to distinguish itself from siblings like get_project, list_projects, or validate_project.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no when-to-use guidance, no prerequisites, and no mention of alternatives. The only hint that this should be called before other project-scoped operations comes from the tool name, not the description.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.