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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered; the description adds genuinely new behavior — default ordering by newest activity, 20-per-page paging, and that no send capability exists anywhere in the surface. It stops short of describing the thread object's fields, which matters since there is no output schema.

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 resource and ordering, and every routing sentence carries information. There is some redundancy — 'newest activity first' is restated as 'Threads, newest first — the conversation view' — which slightly dilutes an otherwise tight block.

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 an 8-parameter read tool with no output schema, the description covers ordering, page size, two key filters and all plausible sibling substitutions. The main residual gap is the shape of a returned thread (fields, participants, unread state), which the agent must infer.

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 a bump by explaining the intent behind two filters — campaignId as 'review one campaign's responses' and keyword as finding 'a specific person' — which reframes the schema's 'Search names and message bodies'. The remaining six filters (tags, type, platform, emailAccountId, linkedAccountId, page) are left entirely to 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 concrete resource framing — 'The unified inbox: LinkedIn and email threads with prospects' — plus ordering and page size. It explicitly distinguishes itself from conversation_get, lead_get and analytics_campaign, so an agent can route 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 for two filters ('campaignId to review one campaign's responses', 'keyword to find a specific person') and names three alternatives with the exact scenario each serves. It also states a boundary case ('Nothing here sends'), closing off a plausible but wrong intent.

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