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

There are no annotations, so the description carries the full burden; it explicitly states 'Reads only,' disclosing that this is a non-mutating operation. It also reveals return characteristics — each entry, hours per worker, and running totals 'as integer cents with formatted amounts' — which is useful behavioral context beyond the 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?

The description is a single, front-loaded sentence that immediately names the action and resource, then enumerates the returned content without wasted words. The final 'Reads only' is compact and earns its place as a safety-relevant clarification.

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?

With no output schema and no annotations, the description covers the essentials: what is read, how the card is identified, and exactly what the return includes. It does not cover error behavior or ambiguous-client handling beyond the schema note, but for a simple read operation the definition is substantially 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?

Schema coverage is 100%: the only parameter 'card' already explains the JC number or client name format and the single-card disambiguation rule. The description's phrase 'by JC number or client' echoes the schema rather than adding new semantic content, so the baseline 3 is appropriate.

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 states a specific verb and resource — 'Read one job card in full' — with a clear scope: by JC number or client, returning labor entries, materials, hours per worker, and running totals. It also says 'Reads only,' distinguishing it from mutating siblings like job_card_create, job_card_log_labor, and job_card_update_status, and from job_card_list which reads multiple cards.

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 implies its use case: you need the full detail of a single job card, not a summary or list. However, it never names alternatives or says when not to use it — e.g., job_card_summary for totals or job_card_list for browsing — leaving the choice partly to inference.

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