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

Annotations already establish read-only, idempotent, non-destructive, closed-world behavior. The description adds useful behavioral context beyond that: it discloses return content (cause, immediate fix, fallback route) and the no-match branch with checks to run. It does not discuss rate limits or auth, but for a read-only diagnostic tool the remaining gap is minor.

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?

Two tightly packed sentences with no wasted clauses. The purpose and input expectation are front-loaded, followed immediately by the return behavior and the exclusion.

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?

Despite having no output schema, the description explains both the success return shape and the no-match outcome. It also covers the key input pattern and names the alternative tool, so an agent has everything needed to decide and invoke correctly.

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%, so all five parameters are already documented. The description adds only illustrative error values and says to paste 'the exact error and provider id,' which reinforces usage but does not meaningfully expand parameter meaning beyond the schema.

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 and resource ('Diagnose a failing third-party API call') and enumerates the error classes it handles (429, 402, 529, insufficient_quota, etc.). It also distinguishes itself from the 'decide' sibling, so an agent can route without opening schemas.

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 explicit timing ('before you retry or swap') and an explicit exclusion with the alternative named: 'Not for picking a provider (decide).' This is exactly the when/when-not/alternative guidance the dimension asks for.

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