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

Goes well beyond the annotations by disclosing blast radius: the edit applies everywhere at once, including on leads already carrying the tag and in past reply-sentiment reporting, so changing `interest` rewrites history rather than reclassifying going forward only. That is exactly the non-obvious side effect an agent needs before mutating.

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?

Front-loaded with the action, then blast radius, then sibling routing — good ordering with little waste. The final sentence about deletion does not earn its place because it is factually wrong given tag_delete exists.

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 with full schema coverage and annotations declaring idempotent/non-destructive, the description covers the important unknowns: scope of effect and alternatives. Minor gaps remain on partial-update semantics and what the call returns (no output schema).

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 the baseline is 3; the description earns an extra point by explaining the retroactive effect of the `interest` parameter. It stops short of clarifying that 'rename' maps to the ambiguously-described `content` field ('Body text'), and does not say whether params are optional/partial updates.

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 ('Rename a tag or change its sentiment classification') and immediately differentiates itself from lead_update and campaign_update. An agent can tell exactly which entity this mutates 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?

Explicit routing: use lead_update to tag a lead, campaign_update for a campaign's own tag. That is strong when-to-use guidance. However, the closing claim 'There is no tool to delete a tag' is contradicted by the sibling tool list, which contains tag_delete, so one guidance sentence is actively misleading.

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