credentials_set

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

With no annotations, the description carries the full burden and does well: it discloses AES-256-GCM encryption at rest, the storage path ~/.aibtc/credentials.enc, and that an existing service/key pair is overwritten. It omits whether an unlocked vault/password is required before writing and what happens on failure.

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?

The first two sentences are tight and front-loaded with the operation, encryption, and upsert rule. The trailing tip about earning_opportunities is off-topic filler that does not earn its place in a credential-storage definition.

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 3-parameter mutation tool with no annotations and no output schema, the description covers storage, encryption, and overwrite behavior adequately. It still leaves gaps on required vault state and return/error behavior that an agent would need before calling.

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 the three parameters (service, key, value) are already documented with examples. The description adds only the 'service/key pair' framing as the identity for the upsert, which is a small increment over 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?

The description uses a specific verb+resource ('Store or update a credential') and names the exact effect on the stored file. It implicitly contrasts with credentials_get/list/delete through the write framing, but never names those siblings explicitly.

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?

There is no statement of when to use this versus credentials_get, credentials_list, or credentials_delete, and no prerequisites are given. The only routing hint points to earning_opportunities, which is unrelated to invoking this tool.

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