Execute read-only SQL queries with named parameter binding, capping results at a configurable limit up to 500 rows.
Run a read statement. Use :name binds in params_json. Results are capped by limit (max 500).
| Name | Required | Description | Default |
|---|---|---|---|
| sql | Yes | ||
| limit | No | ||
| params_json | No | {} | |
| session_name | No | default |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations provided, the description carries the disclosure burden. It does clarify that the operation is read-only and that results are capped at a maximum of 500, which are useful behavioral details. It does not mention prerequisites such as an active session or behavior on invalid binds/limits, so the behavioral picture is incomplete.
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 three short sentences with no filler: purpose, bind syntax, and result cap are each covered once and front-loaded. Every clause earns its place, and nothing needs to be removed.
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?
The tool has four parameters and no annotations, and the description covers sql, params_json, and limit but is silent on session_name and the need for an established connection/session. The presence of an output schema means return values do not need elaboration, but the missing invocation prerequisite keeps this from being complete.
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, and it does for most parameters: sql is described as a read statement, params_json is explained as holding :name named binds, and limit is documented as a result cap. session_name is left entirely unexplained, which prevents a perfect score.
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 states a clear action — 'Run a read statement' — which identifies the tool as a read-only query operation and distinguishes it from the write-oriented siblings like db_execute, db_insert, db_update, and db_delete. It does not explicitly name an alternative, but the read/write contrast gives an agent enough signal to pick it correctly.
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 phrase 'read statement' implies this is for SELECT-style queries, so an agent can infer when to use it among mutation siblings. However, it never explicitly states when not to use it or points to db_execute for non-read statements, so the guidance is implied rather than prescriptive.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.