compare_plan_summaries

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds minimal behavioral context beyond naming the inputs (e.g., 'redacted' suggests the summaries are sanitized), but it does not disclose output details, performance implications, or potential side effects. Since annotations cover the key traits, a mid-range score is appropriate.

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 a single, front-loaded sentence that efficiently conveys the core action and inputs. There is no fluff, redundant information, or repeated schema content. It earns a top score for clarity and brevity.

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?

While an output schema exists to document return values, the description does not explain the comparison's purpose or use cases, nor does it clarify when to choose this tool over similar siblings. It also leaves database_name's meaning ambiguous. Given the tool's moderate complexity and the availability of an output schema, the description is minimally adequate but lacks useful context.

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 67%, with baseline_summary and candidate_summary having brief descriptions ('Baseline plan summary.'), but database_name lacks any description. The tool description adds context about what the summaries contain ('execution-plan summaries and sourced metrics'), helping agents understand the input objects' purpose, but it does not clarify the role of database_name. This partial compensation over the schema's sparse parameter info earns a 3.

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 uses a specific verb ('Compare') and clearly identifies the target resources ('arbitrary redacted execution-plan summaries and sourced metrics'). This distinguishes it from sibling tools like compare_query_plans, which focus on raw query plans, and compare_schemas, which focus on schema objects.

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 provides no guidance on when to use this tool versus alternatives such as compare_query_plans or compare_query_results. It does not state prerequisites, exclusions, or typical use cases, leaving the agent to infer appropriate usage from the name and description alone.

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