show_variables

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

The description explicitly labels the operation as '[READ]', which is a critical behavioral disclosure. Since no annotations are provided, this serves as the primary safety signal. However, it does not disclose other behaviors that might be relevant, such as whether the read is from a live connection, whether the returned variables are system-wide (not session), or any potential performance implications. It adds context beyond the bare tool name but leaves gaps.

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 remarkably concise: a one-line purpose, then a compact Args list. Every line earns its place. The '[READ]' prefix front-loads the most critical behavioral fact. No filler or redundant text.

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?

For a simple read-only listing tool with no output schema and no annotations, the description covers purpose, read-only nature, and parameter details sufficiently. It is missing a note on the return format (e.g., a list of key-value pairs), which an agent might need to interpret results, but this gap is not critical for a straightforward SHOW GLOBAL VARIABLES. The lack of guidance on when to use vs 'show_status' slightly reduces completeness.

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?

The input schema only provides types and titles for 'pattern' and 'target'. The description adds substantial meaning: it explains 'pattern' as an optional substring filter with concrete examples ('innodb_buffer', 'max_connections'), and explains 'target' as a config-based target name with a note to omit for the default. This fully compensates for the low schema description coverage.

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 and resource: '[READ] Global variables (SHOW GLOBAL VARIABLES)'. This is specific and aligns with the tool name. However, it does not explicitly contrast itself with the sibling tool 'show_status', which could be confused by an AI agent. The purpose is clear on its own, but lacks sibling differentiation.

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 parameter-level usage instructions (how to use 'pattern' and 'target') but gives no guidance on when to choose this tool over alternatives like 'show_status' or 'set_global_variable'. There is no explicit context or exclusions, leaving the agent to infer appropriate usage from the tool name and purpose.

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