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

Annotations only state the safety profile (not read-only, not idempotent, not destructive); the description adds substantive behavior beyond them: entries are append-only and never edited, retraction is the only correction path, action codes are validated against the match's current possible next steps, and a rejected code's error enumerates every applicable step. That is real operational context an agent could not derive from the annotations.

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?

One dense paragraph, but front-loaded with the core action and organized so each clause adds a distinct rule (mode semantics, code validation, open/closed constraint, append-only). It is longer than typical but nearly every sentence earns its place; minor tightening would still help readability.

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 non-idempotent append mutation with an output schema present, the description covers the essentials an agent needs: what gets written, which fields are mutually exclusive, the validation rule for codes, and how to undo a mistake. Return values are rightly left to the 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, but the description adds genuine semantic value: it explains that body carries no code for comments, that code is required on action and rejected on comment, and that the code must be one of the match's current possible next steps (cross-field validation with error feedback). It stops short of describing the body's 2000-char limit or format details already in 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?

Opens with a specific verb+resource: 'Append an entry to a takedown's timeline.' It then distinguishes the two modes (comment vs action) and names the sibling tools that matter (get_match for valid codes, retract_takedown_event for reversal), so an agent can separate it from add_asset, update_takedown, or retract_takedown_event without opening a 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?

Gives explicit when-to-use conditions: comment for freeform progress notes, action for performed steps requiring a code; and an explicit when-not: steps only log on an open takedown while comments also work on closed ones. It also routes the agent to get_match for the current possible next steps and to retract_takedown_event for mistakes.

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