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

Annotations already cover safety (readOnly, idempotent, non-destructive, closed-world), and the description goes well beyond them: stateless edge call, 32 KB payload cap, 60 RPM throttle, demo flag, L402 payment of 10 sats, and HTTP 400 on invalid input. This is exactly the runtime context annotations cannot express, though the payment gating is stated tersely and its interaction with a 'read-only' call is not explained.

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?

Front-loaded with purpose, then usage, then operational constraints — a sensible order with no filler. However the second half is a dense semicolon-chained run of limits, payment, and error codes that would scan better as discrete clauses.

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 3-parameter, fully-described, output-schema-backed tool, the description supplies everything an agent still needs: trigger conditions, the sibling alternative, size/rate ceilings, and failure mode. Return values are correctly left to the output schema rather than duplicated.

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 coverage is 100% with enums on both dialect parameters, so the baseline is 3. The description adds a claim that 'target_dialect' defaults to 'sqlite', which conflicts with the schema listing it as required — potentially misleading an agent into omitting it. The 'sql_code' size limit is the only genuinely additive parameter fact.

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 a specific verb and resource ('Transpiles SQL queries and DDL schemas') plus the exact scope (PostgreSQL, MySQL, SQLite) and the concrete work performed ('rewriting functions and syntax quirks'). 'Transpile' is distinct from sibling verbs like synthesize_sql_query, validate_sql_query_ast, and analyze_query_plan, so an agent can separate it without opening a schema.

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?

Gives two positive triggers — migrating application queries across backends and testing against in-memory SQLite — and an explicit exclusion routing to synthesize_sql_query for natural-language query generation. When-to-use and when-not-to-use are both stated.

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