snap_compare

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

Annotations declare readOnlyHint=true and destructiveHint=false, and the description is consistent with a read-only comparison. It adds useful context that 'b' may be 'live' (comparing against running values) and that a numeric tolerance applies, but says nothing about how the diff is reported or whether tolerance affects matching vs. output.

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 compact sentence, front-loaded with the core action and immediately naming the alternative operand values. No wasted words, though the parenthetical slightly crowds the tolerance clause.

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?

An output schema exists, so return values need not be described, and annotations cover the safety profile. However, for a 4-parameter tool with 0% schema description coverage, the undefined 'symbols' parameter and the unspecified tolerance semantics/default leave the agent short of full 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?

Schema coverage is 0%, so the description carries the burden. It explains 'a' and 'b' (including the 'live' sentinel) and mentions tolerance as numeric, but the 'symbols' filter parameter is entirely undocumented in both schema and description, leaving a real gap.

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 verb ('Diff') and resource (snapshot), and clarifies the second operand can be another snapshot or 'live'. It is clear without needing the schema, though it does not explicitly distinguish itself from sibling comparison tools like rec_compare or exp_compare.

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 guidance on when to use this versus rec_compare/exp_compare, no prerequisites (does snapshot 'a' need to exist? is 'live' a running PLC?), and no exclusions. The agent must infer usage entirely.

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