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

With no annotations, the description carries the full burden. It transparently discloses the key side effect: 'This CLAIMS the investigation (records the caller as claimant).' It also details what is returned, including the raw transcript. It does not mention what happens if already claimed or permission requirements, but the core behavioral trait is clearly disclosed, which is strong given no annotation support.

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 description is dense but every sentence earns its place: purpose, identifier format, claiming warning, alternative tool, and return payload structure. It is front-loaded with the most important action and uses clear formatting (bold for CLAIMS) to highlight critical behavior. No filler words.

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?

Despite having no output schema, the description lists all expected return fields (id, publicSlug, headline, flow, channelId, threadTs, createdAt, claimedBy, sessionEntries), eliminating ambiguity about the response. It also covers the side effect and the identifier format, making it self-contained for an agent to invoke correctly. For a simple one-parameter tool, this is exceptionally complete.

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?

The schema already describes the parameter idOrSlug with 100% coverage. The description adds a concrete example ('happy-otter-42') and clarifies that both UUID and public slug are accepted, which enriches the schema text. For a single parameter, this is sufficient extra value beyond 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 opens with a specific verb+resource: 'Claim a Fixter investigation for the calling user and fetch its full transcript.' It clearly states the two actions (claim and fetch) and the resource (investigation). It also distinguishes itself from the read-only sibling get_investigation_brief by emphasizing the claiming aspect, making the purpose unambiguous.

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?

The description provides explicit usage guidance: 'only call it when the user intends to work on the investigation' and names the alternative tool for read-only access ('use get_investigation_brief'). This directly tells the agent when to use this tool versus a clear alternative.

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