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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds genuinely useful behavior beyond that: match semantics (exact or substring), the bounded corpus it searches ('all known... in the register'), and the return shape including a citable URL. It says nothing about no-match behavior or result limits when many errors match, which is why it stops short of a 4.

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 tight sentences: what it matches, when it is the right choice, and what comes back. The usage hint is front-loaded with the resource scope and every sentence carries distinct information.

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 two-parameter, read-only lookup with no output schema, the description covers purpose, matching behavior, and the shape of the return value including the citable URL, so an agent could call it correctly from the description alone. The only gap is what happens on a miss (empty result vs. suggestion), which is minor for this tool class.

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 100%, so both parameters are already documented, giving a baseline of 3. The description earns an extra point by explaining that substring matching is supported, which tells the agent a partial error string is a valid input — meaning the schema alone does not convey.

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 (exact/substring match) and a specific resource (the register of Copilot Studio error codes and messages), and scopes it clearly enough to separate it from the sibling friction/pattern lookups. The example string ('FlowActionTimedOut') removes any ambiguity about what an 'error' argument looks like.

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?

Explicitly names the trigger condition: use this when you already hold a verbatim error string, and claims it is 'the fastest path' in that case. It never names the alternative to use when you don't have a verbatim string (e.g. concept-level search), so exclusion guidance is implied rather than stated.

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