Validate a single SELECT statement and estimate bytes processed without running it, so you can catch query errors and assess cost before execution.
Validate a single SELECT and estimate bytes without executing it. Named parameters use @name in SQL.
| Name | Required | Description | Default |
|---|---|---|---|
| sql | Yes | ||
| account | No | ||
| location | No | ||
| parameters | No | ||
| project_id | No | ||
| maximum_bytes_billed | No |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely new behavior: this performs validation and returns a byte estimate with no execution, plus the '@name' parameter convention. It stops short of saying what happens on invalid SQL or whether the estimate is an upper bound.
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?
Two short sentences, front-loaded with the core capability, no filler. The parameter convention note earns its place.
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?
An output schema exists, so return values need no explanation, and the annotations carry the safety profile. However, for a 6-parameter tool with zero schema coverage, key semantics (account/location/project_id scoping, maximum_bytes_billed behavior, error behavior on invalid SQL) are left entirely unaddressed.
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% — sql, account, location, project_id, and maximum_bytes_billed are all undocumented in both schema and description. The one compensating detail ('Named parameters use @name in SQL') is valuable for the parameters array but leaves five parameters unexplained, so the description does not fill the 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?
Specific verb + resource: 'Validate a single SELECT and estimate bytes without executing it.' The 'without executing it' clause implicitly separates it from the run_query sibling, though it never names that sibling. The 'single SELECT' constraint also usefully narrows scope.
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 'without executing it' phrasing implies this is a pre-flight check before run_query, but the description never states when to use this versus run_query directly, nor any prerequisites. Usage is inferable rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.