LightCMS

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

Adds security validation behavior ('Validates file type and MIME type') and infrastructure constraints ('MCP transport size limits') not present in annotations. Clarifies upsert/replacement semantics. Annotations declare non-destructive operation, and description frames replacement as a convenience feature rather than data destruction.

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?

Three tightly focused paragraphs: action/replacement behavior, content provision options with clear bullet structure, and validation notice. No redundant text; every sentence conveys distinct operational information. Well front-loaded with primary action.

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?

Comprehensive coverage of upload semantics, security constraints, and transport limitations for a 5-parameter file operation. Absence of output schema is noted but description sufficiently covers input concerns and behavioral expectations for successful invocation.

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?

With 100% schema coverage (baseline 3), description adds crucial semantic guidance: specifies mutual exclusivity ('via one of'), size thresholds (>100KB) for choosing between file_path and data_base64, and explains the replacement semantics of serve_path parameter beyond the schema's basic definition.

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?

States specific action ('Upload or replace') and resource ('asset in the asset library'). Explicitly distinguishes from sibling delete_asset by noting replacement happens 'in place — no need to delete first', and implicitly distinguishes from upload_asset_from_url by specifying local file content provision methods.

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?

Provides clear operational guidance: explains replacement behavior (re-uploading to same serve_path replaces existing file) and selection criteria for content sources (file_path preferred for >100KB to avoid transport limits vs data_base64 for small files). Stops short of explicitly naming upload_asset_from_url as the alternative for remote URLs.

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