email_blacklist

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

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses deprecation status (a non-obvious behavioral trait), but says nothing about authentication expectations, whether re-adding an existing address is idempotent, or how many addresses can be submitted at once, leaving real gaps for a mutation tool.

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 short clauses with zero waste, and the most decision-relevant information (the deprecation redirect) is front-loaded before the purpose statement.

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 simple three-parameter mutation with full schema coverage and no output schema, the description covers purpose and lifecycle status adequately. It is not rich on operational behavior, but nothing essential to calling it correctly is missing.

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 three parameters (email, apiKey, restEndpoint) are already documented in the schema. The description only implies that the target is an email list and adds no format, limit, or auth detail beyond the structured fields — 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 specific verb and resource ('Add email addresses to the blacklist') and immediately flags itself as deprecated in favor of the sibling tool email_blocklist, so an agent can distinguish it from the near-identically named alternative 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?

Explicitly names the condition that should select another tool: '[DEPRECATED: Use email_blocklist]'. This is a direct when-not-to-use statement with a named alternative, which is the strongest form of routing guidance.

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