diff_erds

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

With no annotations, the description carries the full transparency burden and does so thoroughly. It discloses that unchanged items are omitted, that text-parsed sides yield different IDs causing many added/removed entries, that import behavior is full-replace, and that summary aggregates only entities while arrays contain domain/relationship changes — all beyond the schema.

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 sentences, each packed with distinct information: what is compared, when to use it, and how to read the output. No filler or redundancy; the most important action and scope appear first.

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?

Despite having no output schema, the description tells the agent what to expect from the result ('summary aggregates entities only; see the arrays') and explains the core behavioral caveat (ID mismatch). This is sufficient for an agent to correctly invoke the tool on 2-parameter inputs and interpret the response.

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 schema already documents the before/after alternatives (file, erdId, sql, dbml), so the description doesn't repeat those. It does add meaningful context about 'a side freshly parsed from text' having different IDs, which directly clarifies the behavior for sql/dbml inputs and complements the schema rather than merely restating it.

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 'Compares two ERD sources' and explicitly lists the compared components (entities/attributes/domains/relationships) and the 'unchanged omitted' behavior. This clearly distinguishes it from sibling tools like import_sql/import_dbml, making its purpose unmistakable.

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 frames this as 'a dry run before full-replace import_sql/import_dbml', providing a direct use-case and naming the alternative tools. It also warns that a side 'freshly parsed from text has different ids' and that behavior matches 'full replace', guiding the agent on when the results are expected and how to interpret them.

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