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

Annotations already cover the safety profile (readOnly=true, idempotent=true, non-destructive), so the bar is lower; the description instead adds real behavioral context: the null-list-means-backlog convention, board-order delivery of cards, threaded comments, and the tie-in of description_version as an input for preview_description_update/update_description. It stops short of static pagination or rate-limit notes.

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 core action, then a single dense enumeration, closing with the input constraint. The result-list parenthetical is long but each clause carries usable information. Slightly heavy, but no filler sentences.

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?

No output schema exists, so the description bears the full burden of describing return values, and it does so item by item, including edge semantics (null list = backlog) and card ordering. An agent has everything needed to call this correctly and interpret the result.

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% and there is only one parameter, so the baseline is 3. The description still adds value the schema lacks: the id is explicitly the epic uid and there is deliberately no project_id parameter, plus where to obtain the uid.

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 ('Read one epic in full') and then enumerates the returned surface: AgileHero Markup description with block ids, description_version, name, number, dates, assignees, checklists, cards and threaded comments. It is clearly distinguishable from siblings like list_epics, get_card and update_epic.

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 the selection signal for a sibling ('this is the way to list all cards of an epic and see which are to do, in progress or done') and points to the producers of the required id ('Epic uids come from list_epics or search'). It does not state an explicit when-not-to-use case, but the routing information is concrete.

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