query_history_compare_candidates

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

The readOnlyHint is already declared and the description reinforces it with 'nothing is run,' which is a useful confirmation that the substitution is a dry run. Beyond that it doesn't disclose result ordering semantics or what 'heaviest' is measured by (duration, cost, rows).

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?

A single dense sentence with no filler. The core action leads, and the clarifying parentheticals follow, though parsing the nested quotes and backticks takes some effort.

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, the description should indicate what comes back. It implies the returned queries have their table name rewritten, but it never says the result is a list of candidate queries bounded by 'limit,' leaving the return shape to inference.

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 0%, so the description must compensate. It partially does: it documents that 'table' uses a database.table format and that 'new_table' replaces the table name in the matched queries. The 'limit' parameter (default 8) is never explained.

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 (find the heaviest read-only queries in history) and resource (queries reading a given table), and clarifies the table-name substitution. It reads as a candidate-selection step ahead of query_history_compare_start, but it doesn't explicitly name or distinguish itself from that sibling set.

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?

No when-to-use guidance is given. With siblings like query_history_compare_start, query_history_compare_status and query_history_compare_cancel in the same family, the agent must infer that this tool feeds the comparison workflow rather than starting it.

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