Suggest conservative index candidates for slow single-table queries by analyzing SQL and existing indexes. Validate each recommendation with EXPLAIN before applying any DDL.
Conservative index candidates for single unquoted table queries. Requires EXPLAIN validation; never applies DDL.
| Name | Required | Description | Default |
|---|---|---|---|
| sql | Yes | ||
| existingIndexes | No |
Changes observed during successful MCP inspections.
v0.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed-world scope, so safety is covered. The description still adds real value by stating it 'never applies DDL' (reinforcing advisory-only behavior) and that output 'Requires EXPLAIN validation', which is procedural context the annotations do not carry.
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 tight sentences with the scope constraint and the advisory nature front-loaded. No filler; every clause carries information.
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?
With no output schema and no annotation coverage of parameters, the definition should explain the sql input and existingIndexes role, and ideally the shape of returned candidates. It conveys the safety posture well but leaves the calling contract under-specified.
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% and the description never mentions the two parameters. The sql input format and the purpose of existingIndexes (why pass known indexes) are left entirely unexplained; the vague 'single unquoted table queries' phrase hints at a sql constraint but does not define 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?
States a specific action and resource ('index candidates') plus an explicit scope restriction ('single unquoted table queries') and a quality stance ('conservative'). This is far more than a restatement of the name, but it distinguishes itself from no sibling tool (analyze_query, explain_plan) by name or role.
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?
'Requires EXPLAIN validation' gives downstream workflow context and 'never applies DDL' bounds the action, but there is no explicit when-to-use guidance relative to analyze_query or explain_plan. An agent must infer that this is advisory-only.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.