get_active_build

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

With no annotations provided, the description fully discloses behavior: it is read-only, details the return dictionary fields including the 'stale' boolean with its condition (compile_commands.json newer than index), and the auto-detection of project_root.

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?

The description is concise with three well-organized parts: purpose statement, usage advice, and return format. Every sentence is informative, and the structure is easy to parse.

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?

For a simple tool with one optional parameter, the description covers all necessary context: purpose, when to use, return schema, and behavioral notes. No output schema is needed because the return fields are described in plain language.

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?

The input schema already describes the 'project_root' parameter, but the description adds value by stating it is 'Auto-detected from CWD if omitted', providing important default behavior beyond the schema.

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 starts with a clear verb phrase 'Return metadata about the most recently indexed build configuration', specifying the resource precisely. It distinguishes this tool from siblings like reindex_file or reset_index by focusing on read-only metadata retrieval.

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?

The description explicitly states 'Call at session start' and lists three specific checks (index existence, symbol count, staleness). This provides clear context for when to use the tool, though it does not mention when not to use it or alternative tools.

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