Set primary provider

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

Annotations declare readOnlyHint=false and destructiveHint=false, so the write-not-destructive profile is already covered. The description adds real behavioral context beyond that: deprecation status and the no-op semantics of 'false'. It does not, however, explain the idempotency_key behavior or whether repeated 'true' calls are safe, which would round this out.

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, front-loaded sentences with zero filler: deprecation first, semantics second, migration path last. Every sentence earns its place and the most decision-relevant fact (deprecated) leads.

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 deprecated compatibility tool with no output schema and annotations covering the safety profile, the description covers purpose, migration path, and the no-op case. The only gap is unstated idempotency/repeat-call behavior, which is minor here.

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 75%, so the schema already documents project_id, provider_id, and the 'primary' flag's meaning. The description's note that 'true promotes priority 0' largely restates the 'primary' schema description. It adds nothing about idempotency_key, the one parameter left undocumented in both places.

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 names a specific resource and outcome ('promotes priority 0') and immediately frames the tool as a deprecated compatibility shim. It distinguishes itself from sibling set_provider_priority by routing new usage there. An agent can identify this tool's job without opening the schema.

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?

It gives explicit when-to-use guidance: use set_provider_priority for new calls, implying this is only for legacy compatibility. It also clarifies that 'false' is a legacy no-op, telling the caller when calling is effectively pointless. This is exactly the alternative-selection signal agents need.

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