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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds meaningful non-structured context: results come from Snapback's library, are ranked, and carry failure_class/root_cause/fix_suggestion, and the tool is meant as a self-correction step before execution.

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?

Three short sentences, front-loaded with the 'BEFORE running' constraint in caps, which is exactly the operative signal. Minor redundancy between 'BEFORE running' and 'Call this before executing a plan', which keeps it from a 5.

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 re-explained; with all parameters optional and fully documented, the agent has enough to invoke it. The only gap is the absence of any explicit sibling routing for post-hoc failure diagnosis.

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 100% — tags, limit, and agent_stack are all documented in the schema with examples and defaults. The description adds nothing about how a 'given agent setup' maps to these parameters, so the baseline 3 applies.

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 concrete verb and resource ('get known failure patterns for a given agent setup') plus the returned shape, so the agent knows exactly what it gets. It implies differentiation from the diagnose_* siblings via 'BEFORE running' (preventive vs. post-hoc), but never names a sibling or draws the contrast explicitly, so it falls short of a 5.

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?

Gives clear timing guidance: 'Call this before executing a plan and self-correct.' This tells the agent when the tool belongs in a workflow. There is no statement of when NOT to use it or which sibling to prefer for post-hoc diagnosis, so it is context-rich but not exclusionary.

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