Ludus FastMCP

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

With no annotations provided, the description carries full burden for behavioral disclosure. It states this is a 'grant' operation (implying mutation/write), but doesn't describe what 'range' refers to, whether this requires admin permissions beyond the parameter note, what happens if access already exists, or any rate limits/constraints. The return value is mentioned but not explained. For a mutation tool with zero annotation coverage, this leaves significant behavioral gaps.

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 appropriately sized and well-structured with clear sections (purpose, args, returns). The purpose statement is front-loaded. However, the 'Args' and 'Returns' sections could be more integrated into natural language, and some details in parameter explanations are terse but not wasteful.

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?

Given 3 parameters with 0% schema coverage, no annotations, and an output schema (implied by 'Returns'), the description does an adequate but incomplete job. It covers the basic purpose and parameters but lacks crucial context: what 'range' means in this system, permission semantics, admin requirements beyond the parameter note, and what the 'Grant result' output contains. The output schema existence reduces but doesn't eliminate the need for behavioral completeness.

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 0%, so the description must compensate. It lists all three parameters with brief explanations: target_user_id (user to grant to), permissions (list with enum-like values), and user_id (optional, admin only). This adds meaningful context beyond the bare schema. However, it doesn't explain permission semantics (what 'admin' entails vs 'write'), format expectations for user IDs, or default behaviors when user_id is null. Baseline 3 reflects partial compensation for the coverage gap.

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 clearly states the verb ('grant access') and resource ('range for another user'), making the purpose unambiguous. However, it doesn't explicitly differentiate from sibling tools like 'clear_range_access' or 'revoke_range_access', which would require mentioning it's specifically for granting (not clearing/revoking) access.

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 provides no guidance on when to use this tool versus alternatives like 'clear_range_access' or 'revoke_range_access'. It mentions 'admin only' for the optional user_id parameter, but this is parameter-specific guidance rather than overall usage context. No explicit when/when-not scenarios or prerequisites are stated.

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