get_project_structure

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

With no annotations provided, the description carries the full burden. It clearly conveys that this is a read-only operation (repeated 'Return' statements) and explains the output structure (instruments, field counts, type breakdowns, event/instrument matrix). It stops short of stating edge cases like longitudinal vs non-longitudinal behavior explicitly, but the mention of 'for longitudinal projects' adds useful behavioral context. No contradictions.

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 unusually efficient: three short paragraphs, each with a distinct purpose (overview, usage timing, output details). No word is wasted; the 'Returns:' line clearly signals the output type. It is front-loaded with the core purpose, making it easy for an agent to scan quickly.

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 tool with no parameters and a straightforward output schema, the description is complete. It tells the agent what to expect (compact overview, instruments with counts and types, optional event matrix), when to use it (first call), and what form the output takes (JSON object). It does not over-explore because the output schema already exists, and sibling tools cover other concerns.

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 tool has zero parameters, so the schema fully covers that aspect. Baseline for 0 params is 4. The description doesn't need to explain parameters and instead focuses on return semantics, which is appropriate.

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 opens with a specific action ('Return a compact structural overview') and clearly identifies the resource (REDCap project). It further distinguishes this tool from siblings by specifying exactly what it returns (instruments with field counts and type breakdowns, plus an event/instrument matrix for longitudinal projects), making it clear that this is not a full metadata or record dump.

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 says 'Useful as a first call when starting work on an existing project', providing clear when-to-use guidance. It does not mention alternatives or when-not-to-use, but the context of sibling tools (get_project_info, get_metadata, get_instruments) and the 'compact' nature imply it is a quick orientation tool, not a replacement for detailed queries.

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